(1) What will be output if you will compile and execute the following c code?
void main(){
int i=320;
char *ptr=(char *)&i;
printf("%d",*ptr);
}
(a)320
(b)1
(c)64
(d)Compiler error
(e)None of above
Output: (c)
Explanation:
As we know size of int data type is two byte while char pointer can pointer one byte at time.
Memory representation of int i=320
So char pointer ptr is pointing to only first byte as shown above figure.
*ptr i.e. content of first byte is 01000000 and its decimal value is 64.
How to represent char, int and float data in memory?
Data type tutorial.
(2) What will be output if you will compile and execute the following c code?
#define x 5+2
void main(){
int i;
i=x*x*x;
printf("%d",i);
}
(a)343
(b)27
(c)133
(d)Compiler error
(e)None of above
Output: (b)
Explanation:
As we know #define is token pasting preprocessor it only paste the value of micro constant in the program before the actual compilation start. If you will see intermediate file you will find:
test.c 1:
test.c 2: void main(){
test.c 3: int i;
test.c 4: i=5+2*5+2*5+2;
test.c 5: printf("%d",i);
test.c 6: }
test.c 7:
You can absorb #define only pastes the 5+2 in place of x in program. So,
i=5+2*5+2*5+2
=5+10+10+2
=27
What is intermediate file and how to see intermediate file?
Preprocessor tutorial.
(3) What will be output if you will compile and execute the following c code?
void main(){
char c=125;
c=c+10;
printf("%d",c);
}
(a)135
(b)+INF
(c)-121
(d)-8
(e)Compiler error
Output: (c)
Explanation:
As we know char data type shows cyclic properties i.e. if you will increase or decrease the char variables beyond its maximum or minimum value respectively it will repeat same value according to following cyclic order:
So,
125+1= 126
125+2= 127
125+3=-128
125+4=-127
125+5=-126
125+6=-125
125+7=-124
125+8=-123
125+9=-122
125+10=-121
What is cyclic nature of data type?
Data type tutorial.
(4) What will be output if you will compile and execute the following c code?
void main(){
float a=5.2;
if(a==5.2)
printf("Equal");
else if(a<5.2)
printf("Less than");
else
printf("Greater than");
}
(a)Equal
(b)Less than
(c)Greater than
(d)Compiler error
(e)None of above
Output: (b)
Explanation:
5.2 is double constant in c. In c size of double data is 8 byte while a is float variable. Size of float variable is 4 byte.
So double constant 5.2 is stored in memory as:
101.00 11001100 11001100 11001100 11001100 11001100 11001101
Content of variable a will store in the memory as:
101.00110 01100110 01100110
It is clear variable a is less than double constant 5.2
Since 5.2 is recurring float number so it different for float and double. Number likes 4.5, 3.25, 5.0 will store same values in float and double data type.
Note: In memory float and double data is stored in completely different way. If you want to see actual memory representation goes to question number (60) and (61).
Data type tutorial.
(5) What will be output if you will compile and execute the following c code?
void main(){
int i=4,x;
x=++i + ++i + ++i;
printf("%d",x);
}
(a)21
(b)18
(c)12
(d)Compiler error
(e)None of above
Output: (a)
Explanation:
In ++a, ++ is pre increment operator. In any mathematical expression pre increment operator first increment the variable up to break point then starts assigning the final value to all variable.
Step 1: Increment the variable I up to break point.
Step 2: Start assigning final value 7 to all variable i in the expression.
So, i=7+7+7=21
What is break point?
Operator tutorial.
(6) What will be output if you will compile and execute the following c code?
void main(){
int a=2;
if(a==2){
a=~a+2<<1;
printf("%d",a);
}
else
{ break;
}
}
(a)It will print nothing.
(b)-3
(c)-2
(d)1
(e)Compiler error
Output: (e)
Explanation:
Keyword break is not part of if-else statement. Hence it will show compiler error: Misplaced break
Where we can use break keyword?
Control statement tutorial
(7) What will be output if you will compile and execute the following c code?
void main(){
int a=10;
printf("%d %d %d",a,a++,++a);
}
(a)12 11 11
(b)12 10 10
(c)11 11 12
(d)10 10 12
(e)Compiler error
Output: (a)
Explanation:
In c printf function follows cdecl parameter passing scheme. In this scheme parameter is passed from right to left direction.
So first ++a will pass and value of variable will be a=10 then a++ will pass now value variable will be a=10 and at the end a will pass and value of a will be a=12.
What is cedecl and pascal parameter passing convention?
Function tutorial.
(8) What will be output if you will compile and execute the following c code?
void main(){
char *str="Hello world";
printf("%d",printf("%s",str));
}
(a) 11Hello world
(b) 10Hello world
(c) Hello world10
(d) Hello world11
(e) Compiler error
Output: (d)
Explanation:
Return type of printf function is integer and value of this integer is exactly equal to number of character including white space printf function prints. So, printf(“Hello world”) will return 13.
What is prototype of printf function?
Formatted I/O tutorial.
(9) What will be output if you will compile and execute the following c code?
#include "stdio.h"
#include "string.h"
void main(){
char *str=NULL;
strcpy(str,"cquestionbank");
printf("%s",str);
}
(a)cquestionbank
(b)cquestionbank\0
(c)(null)
(d)It will print nothing
(e)Compiler error
Output: (c)
Explanation:
We cannot copy any thing using strcpy function to the character pointer pointing to NULL.
String tutorial.
More questions of string.
(10) What will be output if you will compile and execute the following c code?
#include "stdio.h"
#include "string.h"
void main(){
int i=0;
for(;i<=2;)
printf(" %d",++i);
}
(a)0 1 2
(b)0 1 2 3
(c)1 2 3
(d)Compiler error
(e)Infinite loop
Output: (c)
Explanation:
In for loop each part is optional.
Complete tutorial of looping in C.
(11) What will be output if you will compile and execute the following c code?
void main(){
int x;
for(x=1;x<=5;x++);
printf("%d",x);
}
(a)4
(b)5
(c)6
(d)Compiler error
(e)None of above
Output: (c)
Explanation:
Body of for loop is optional. In this question for loop will execute until value of variable x became six and condition became false.
Looping tutorial.
(12) What will be output if you will compile and execute the following c code?
void main(){
printf("%d",sizeof(5.2));
}
(a)2
(b)4
(c)8
(d)10
(e)Compiler error
Output: (c)
Explanation:
Default type of floating point constant is double. So 5.2 is double constant and its size is 8 byte.
Detail explanation of all types of constant in C.
(13) What will be output if you will compile and execute the following c code?
#include "stdio.h"
#include "string.h"
void main(){
char c='\08';
printf("%d",c);
}
(a)8
(b)’8’
(c)9
(d)null
(e)Compiler error
Output: (e)
Explanation:
In c any character is starting with character ‘\’ represents octal number in character. As we know octal digits are: 0, 1, 2, 3, 4, 5, 6, and 7. So 8 is not an octal digit. Hence ‘\08’ is invalid octal character constant.
Octal character constantan.
Hexadecimal character constant.
(14) What will be output if you will compile and execute the following c code?
#define call(x,y) x##y
void main(){
int x=5,y=10,xy=20;
printf("%d",xy+call(x,y));
}
(a)35
(b)510
(c)15
(d)40
(e)None of above
Output: (d)
Explanation:
## is concatenation c preprocessor operator. It only concatenates the operands i.e.
a##b=ab
If you will see intermediate file then you will find code has converted into following intermediate code before the start of actual compilation.
Intermediate file:
test.c 1:
test.c 2: void main(){
test.c 3: int x=5,y=10,xy=20;
test.c 4: printf("%d",xy+xy);
test.c 5: }
test.c 6:
It is clear call(x, y) has replaced by xy.
What is macro call?
Preprocessor tutorial.
(15) What will be output if you will compile and execute the following c code?
int * call();
void main(){
int *ptr;
ptr=call();
clrscr();
printf("%d",*ptr);
}
int * call(){
int a=25;
a++;
return &a;
}
(a)25
(b)26
(c)Any address
(d)Garbage value
(e)Compiler error
Output: (d)
Explanation:
In this question variable a is a local variable and its scope and visibility is within the function call. After returning the address of a by function call variable a became dead while pointer ptr is still pointing to address of variable a. This problem is known as dangling pointer problem.
Complete pointer tutorial.
(16) What is error in following declaration?
struct outer{
int a;
struct inner{
char c;
};
};
(a)Nesting of structure is not allowed in c.
(b)It is necessary to initialize the member variable.
(c)Inner structure must have name.
(d)Outer structure must have name.
(e)There is not any error.
Output: (c)
Explanation:
It is necessary to assign name of inner structure at the time of declaration other wise we cannot access the member of inner structure. So correct declaration is:
struct outer{
int a;
struct inner{
char c;
}name;
};
Structure tutorial.
Union tutorial.
(17) What will be output if you will compile and execute the following c code?
void main(){
int array[]={10,20,30,40};
printf("%d",-2[array]);
}
(a)-60
(b)-30
(c)60
(d)Garbage value
(e)Compiler error
Output: (b)
Explanation:
In c,
array[2]=*(array+2)=*(2+array)=2[array]=30
Array tutorial.
Array of pointer.
How to read complex pointers.
(18) What will be output if you will compile and execute the following c code?
void main(){
int i=10;
static int x=i;
if(x==i)
printf("Equal");
else if(x>i)
printf("Greater than");
else
printf("Less than");
}
(a)Equal
(b)Greater than
(c)Less than
(d)Compiler error
(e)None of above
Output: (d)
Explanation:
static variables are load time entity while auto variables are run time entity. We can not initialize any load time variable by the run time variable.
In this example i is run time variable while x is load time variable.
What is storage class?
(18) What will be output if you will compile and execute the following c code?
void main(){
int i=5,j=2;
if(++i>j++||i++>j++)
printf("%d",i+j);
}
(a)7
(b)11
(c)8
(d)9
(e)Compiler error
Output: (d)
Explanation:
|| is logical OR operator. In C logical OR operator doesn’t check second operand if first operand is true.
++i>j++ || i++>j++
First operand: ++i>j++
Second operand: i++>j++
First operand
++i > j++
=> 6 > 2
Since first operand is true so it will not check second operand.
Hence i= 6 and j=3
Properties of && operator.
Operator tutorial with examples.
(19) What will be output if you will compile and execute the following c code?
#define max 5;
void main(){
int i=0;
i=max++;
printf("%d",i++);
}
(a)5
(b)6
(c)7
(d)0
(e)Compiler error
Output: (e)
Explanation:
#define is token pasting preprocessor. If you will see intermediate file: test.i
test.c 1:
test.c 2: void main(){
test.c 3: int i=0;
test.c 4: i=5++;
test.c 5: printf("%d",i++);
test.c 6: }
test.c 7:
It is clear macro constant max has replaced by 5. It is illegal to increment the constant number. Hence compiler will show Lvalue required.
What is Lvalue and Rvalue?
How to see intermediate file?
Preprocessor questions and answer.
(20) What will be output if you will compile and execute the following c code?
void main(){
double far* p,q;
printf("%d",sizeof(p)+sizeof q);
}
(a)12
(b)8
(c)4
(d)1
(e)Compiler error
Output: (a)
Explanation:
It is clear p is far pointer and size of far pointer is 4 byte while q is double variable and size of double variable is 8 byte.
What is near pointer?
What is far pointer?
What is huge pointer?
Complete pointer tutorial.
(21) What will be output if you will compile and execute the following c code?
void main(){
int a=5;
float b;
printf("%d",sizeof(++a+b));
printf(" %d",a);
}
(a)2 6
(b)4 6
(c)2 5
(d)4 5
(e)Compiler error
Output: (d)
Explanation:
++a +b
=6 + Garbage floating point number
=Garbage floating point number
//From the rule of automatic type conversion
Hence sizeof operator will return 4 because size of float data type in c is 4 byte.
Value of any variable doesn’t modify inside sizeof operator. Hence value of variable a will remain 5.
Properties of sizeof operator.
Operators tutorial
(22) What will be output if you will compile and execute the following c code?
void main(){
char huge *p=(char *)0XC0563331;
char huge *q=(char *)0XC2551341;
if(p==q)
printf("Equal");
else if(p>q)
printf("Greater than");
else
printf("Less than");
}
(a)Equal
(b)Greater than
(c)Less than
(d)Compiler error
(e)None of above
Output: (a)
Explanation:
As we know huge pointers compare its physical address.
Physical address of huge pointer p
Huge address: 0XC0563331
Offset address: 0x3331
Segment address: 0XC056
Physical address= Segment address * 0X10 + Offset address
=0XC056 * 0X10 +0X3331
=0XC0560 + 0X3331
=0XC3891
Physical address of huge pointer q
Huge address: 0XC2551341
Offset address: 0x1341
Segment address: 0XC255
Physical address= Segment address * 0X10 + Offset address
=0XC255 * 0X10 +0X1341
=0XC2550 + 0X1341
=0XC3891
Since both huge pointers p and q are pointing same physical address so if condition will true.
What is huge pointer?
What is normalization?
Pointer tutorial.
(23) What will be output if you will compile and execute the following c code?
void main(){
char *str;
scanf("%[^\n]",str);
printf("%s",str);
}
(a)It will accept a word as a string from user.
(b)It will accept a sentence as a string from user.
(c)It will accept a paragraph as a string from user.
(d)Compiler error
(e)None of above
Output: (b)
Explanation:
Task of % [^\t] is to take the stream of characters until it doesn’t receive new line character ‘\t’ i.e. enter button of your keyboard.
General meaning of %[^ p]
String tutorial.
(24) What will be output if you will compile and execute the following c code?
void main(){
int a=5,b=10,c=15;
int *arr[]={&a,&b,&c};
printf("%d",*arr[1]);
}
(a)5
(b)10
(c)15
(d)Compiler error
(e)None of above
Output: (d)
Explanation:
Array element cannot be address of auto variable. It can be address of static or extern variables.
What is auto variable?
What is extern variable?
What is static variable?
Array tutorial.
(25) What will be output if you will compile and execute the following c code?
void main(){
int array[3]={5};
int i;
for(i=0;i<=2;i++)
printf("%d ",array[i]);
}
(a)5 garbage garbage
(b)5 0 0
(c)5 null null
(d)Compiler error
(e)None of above
Output: (b)
Explanation:
Storage class of an array which initializes the element of the array at the time of declaration is static. Default initial value of static integer is zero.
Properties of static storage class.
How to read complex array.
(26) What will be output if you will compile and execute the following c code?
void main(){
int array[2][2][3]={0,1,2,3,4,5,6,7,8,9,10,11};
printf("%d",array[1][0][2]);
}
(a)4
(b)5
(c)6
(d)7
(e)8
Output: 8
Explanation:
array[1][0][2] means 1*(2*3)+0*(3)+3=9th element of array starting from zero i.e. 8.
Questions on two dimension array.
Complete tutorial of array.
(27) What will be output if you will compile and execute the following c code?
void main(){
int a[2][4]={3,6,9,12,15,18,21,24};
printf("%d %d %d",*(a[1]+2),*(*(a+1)+2),2[1[a]]);
}
(a)15 18 21
(b)21 21 21
(c)24 24 24
(d)Compiler error
(e)None of above
Output: (b)
Explanation:
In c,
a [1][2]
=*(a [1] +2)
=*(*(a+1) +2)
=2[a [1]]
=2[1[a]]
Now, a [1] [2] means 1*(4) +2=6th element of an array staring from zero i.e. 21.
Concept of complex array.
Concept of complex pointer.
Concept of complex function.
(28) What will be output if you will compile and execute the following c code?
void call(int,int,int);
void main(){
int a=10;
call(a,a++,++a);
}
void call(int x,int y,int z){
printf("%d %d %d",x,y,z);
}
(a)10 10 12
(b)12 11 11
(c)12 12 12
(d)10 11 12
(e)Compiler error
Output: (e)
Explanation:
Default parameter passing scheme of c is cdecl i.e. argument of function will pass from right to left direction.
First ++a will pass and a=11
Then a++ will pass and a=11
Then a will pass and a=12
What is pascal and cedecl parameter passing scheme?
Concept of variable numbers of argument.
(29) What will be output if you will compile and execute the following c code?
void main(){
int x=5,y=10,z=15;
printf("%d %d %d");
}
(a)Garbage Garbage Garbage
(b)5 10 15
(c)15 10 5
(d)Compiler error
(e)Run time error
Output: (c)
Explanation:
Auto variables are stored in stack as shown in following figure.
Stack follow LIFO data structure i.e. last come and first out. First %d will print then content of two continuous bytes from the top of the stack and so on.
Memory map tutorial.
More questions based on memory map.
(30) What will be output if you will compile and execute the following c code?
void main(){
register int i,x;
scanf("%d",&i);
x=++i + ++i + ++i;
printf("%d",x);
}
(a)17
(b)18
(c)21
(d)22
(e)Compiler error
Output: (e)
Explanation:
In c register variable stores in CPU it doesn’t store in RAM. So register variable have not any memory address. So it is illegal to write &a.
Complete tutorial of storage class with examples.
Properties of register storage class.
(31) What will be output if you will compile and execute the following c code?
void main(){
int a=5;
int b=10;
{
int a=2;
a++;
b++;
}
printf("%d %d",a,b);
}
(a)5 10
(b)6 11
(c)5 11
(d)6 10
(e)Compiler error
Output: (c)
Explanation:
Default storage class of local variable is auto. Scope and visibility of auto variable is within the block in which it has declared. In c, if there are two variables of the same name then we can access only local variable. Hence inside the inner block variable a is local variable which has declared and defined inside that block. When control comes out of the inner block local variable a became dead.
Complete tutorial of storage class with examples.
What is auto storage class?
(32) What will be output if you will compile and execute the following c code?
void main(){
float f=3.4e39;
printf("%f",f);
}
(a)3.4e39
(b)3.40000…
(c)+INF
(d)Compiler error
(e)Run time error
Output: (c)
Explanation:
If you will assign value beyond the range of float data type to the float variable it will not show any compiler error. It will store infinity.
Data type tutorial with examples.
Concept of float data type.
(33) What will be output if you will compile and execute the following c code?
void main(){
enum color{
RED,GREEN=-20,BLUE,YELLOW
};
enum color x;
x=YELLOW;
printf("%d",x);
}
(a)-22
(b)-18
(c)1
(d)Compiler error
(e)None of above
Output: (b)
Explanation:
Default value of enum constant = value of previous enum constant +1
Default value of first enum constant=0
Hence:
BLUE=GREEN+1=-20+1=-19
YELLOW=BLUE+1=-19+1=-18
Complete tutorial of enum data type with examples.
(34) What will be output if you will compile and execute the following c code?
void main(){
asm{
mov bx,8;
mov cx,10
add bx,cx;
}
printf("%d",_BX);
}
(a)18
(b)8
(c)0
(d)Compiler error
(e)None of above
Output: (a)
Explanation:
asm keyword is used to write assembly language program in c. mov command stores the constants in the register bx, cx etc. add command stores the content of register and stores in first register i.e. in bx.
How to write assembly language program by c?
Advance c tutorial.
(35) What will be output if you will compile and execute the following c code?
void main(){
enum xxx{
a,b,c=32767,d,e
};
printf("%d",b);
}
(a)0
(b)1
(c)32766
(d)Compiler error
(e)None of above
Output: (d)
Explanation:
Size of enum constant is size of sign int. Since value of c=32767. Hence value of d will be 32767+1=32768 which is beyond the range of enum constant.
Tutorial of data type with examples.
(36) What will be output if you will compile and execute the following c code?
void main(){
signed int a=-1;
unsigned int b=-1;
if(a==b)
printf("%d %d",a,b);
else
printf("Not equal");
}
(a)-1 -1
(b)-1 32767
(c)-1 -32768
(d)Not equal
(e)Compiler error
Output: (a)
Explanation:
What is automatic type conversion?
(37) What will be output if you will compile and execute the following c code?
void main(){
float f=5.5f;
float x;
x=f%2;
printf("%f",x);
}
(a)1.500000
(b)1.000000
(c)5.500000
(d)Compiler error
(e)None of above
Output: (d)
Explanation:
Modular division is not allowed with floating number.
Properties of modular division.
Operators tutorial with examples.
(38) What will be output if you will compile and execute the following c code?
void main(){
int a=-20;
int b=-3;
printf("%d",a%b);
}
(a)2
(b)-2
(c)18
(d)-18
(e)Compiler error
Output: (b)
Explanation:
Sign of resultant of modular division depends upon only the sign of first operand.
Properties of modular division.
Operator’s tutorial with examples.
(39) What will be output if you will compile and execute the following c code?
void main(){
char c='0';
printf("%d %d",sizeof(c),sizeof('0'));
}
(a)1 1
(b)2 2
(c)1 2
(d)2 1
(e)None of above
Output: (c)
Explanation:
Size of char data type is one byte while size of character constant is two byte.
Why character constant is of two byte in c?
(40) What will be output if you will compile and execute the following c code?
void main(){
char *url="c:\tc\bin\rw.c";
printf("%s",url);
}
(a)c:\tc\bin\rw.c
(b)c:/tc/bin/rw.c
(c)c: c inw.c
(d)c:cinw.c
(e)w.c in
Output: (e)
Explanation:
1. \t is tab character which moves the cursor 8 space right.
2. \b is back space character which moves the cursor one space back.
3. \r is carriage return character which moves the cursor beginning of the line.
Complete string tutorial with examples.
Properties of escape characters.
(41) What will be output if you will compile and execute the following c code?
void main(){
clrscr();
goto abc;
printf("main");
getch();
}
void dispaly(){
abc:
printf("display");
}
(a)main
(b)display
(c)maindisplay
(d)displaymain
(e)Compiler error
Output: (e)
Explanation:
Label of goto cannot be in other function because control cannot move from one function to another function directly otherwise it will show compiler error: unreachable label
What is goto keyword.
Complete function tutorial with examples.
(42) What will be output if you will compile and execute the following c code?
void main(){
int i=3;
if(3==i)
printf("%d",i<<2<<1);
else
printf("Not equal");
}
(a)1
(b)48
(c)24
(d)Not equal
(e)Compiler error
Output: (c)
Explanation:
Associative of bitwise left shifting operator is left to right. In the following expression:
i<<2<<1
There are two bitwise operators. From rule of associative leftmost operator will execute first.
i <<><<>
After execution of leftmost bitwise left shifting operator:
so i=i*pow(2,2)
=3*
What is associative?
What is precedence?
Tutorial of bitwise operators.
(43) What will be output if you will compile and execute the following c code?
void main(){
int x=2,y=3;
if(x+y<=5)
printf("True");
else
printf("False");
}
(a)True
(b)False
(c)Compiler error: Lvalued required
(d)Compiler error: Invalid expression
(e)None of above
Output: (a)
Explanation:
Expression x+y<=5
=> 2+3 <=5
=> 5<=5 is true because 5 is either greater than 5 or equal to 5.
Operator tutorial with examples.
(44) What will be output if you will compile and execute the following c code?
void main(){
const int i=5;
i++;
printf("%d",i);
}
(a)5
(b)6
(c)0
(d)Compiler error
(e)None of above
Output: (d)
Explanation:
We cannot modify the const variable by using increment operator.
Properties of const keyword.
Properties of volatile keyword.
Data type tutorial with examples.
(45) What will be output if you will compile and execute the following c code?
void main(){
const int x=25;
int * const p=&x;
*p=2*x;
printf("%d",x);
}
(a)25
(b)50
(c)0
(d)Compiler error
(e)None of above
Output: (b)
Explanation:
const keyword in c doesn’t make any variable as constant but it only makes the variable as read only. With the help of pointer we can modify the const variable. In this example pointer p is pointing to address of variable x. In the following line:
int * const p=&x;
p is constant pointer while content of p i.e. *p is not constant.
*p=2*x put the value 50 at the memory location of variable x.
Properties of const keyword.
What is constant pointer?
Data type tutorial with examples.
(46) What will be output if you will compile and execute the following c code?
void main(){
int i=11;
int const * p=&i;
p++;
printf("%d",*p);
}
(a)11
(b) 12
(c)Garbage value
(d)Compiler error
(e)None of above
Output: (c)
Explanation:
In the following line:
int const * p=&i;
*p i.e. content of p is constant pointer p is not constant pointer. So we can modify the pointer p. After incrementing the pointer it will point next memory location and its content will any garbage value.
Note: We have assumed arbitrary memory address.
To make pointer p as constant pointer write:
int const * const p=&i;
Properties of const keyword.
Properties of volatile keyword.
(47) What will be output if you will compile and execute the following c code?
void main(){
int a=15,b=10,c=5;
if(a>b>c )
printf("Trre");
else
printf("False");
}
(a)True
(b)False
(c)Run time error
(d)Compiler error
(e)None of above
Output: (b)
Explanation:
Relation operator in c always returns 1 when condition is true and 0 when condition is false. So in the following expression
a > b > c
Associative of relational operators are left to right order of execution will be following manner:
Hence in this expression first solve bolded condition: a > b > c
Since condition a>b is true so result will be 1. Now expression became:
1 > c
Since this condition is false so result will be 0. Thus else part will execute.
What is associative?
What is precedence?
(48) What will be output if you will compile and execute the following c code?
void main(){
float f;
f=3/2;
printf("%f",f);
}
(a)1.5
(b)1.500000
(c)1.000000
(d)Compiler error
(e)None of above
Output: (b)
Explanation:
In the following expression:
f=3/2 both 3 and 2 are integer constant hence its result will also be an integer constant i.e. 1.
Properties of floating type numbers.
(49) What will be output if you will compile and execute the following c code?
void main(){
int a=sizeof(a);
a=modify(a);
printf("%d",a);
}
int modify(int x){
int y=3;
_AX=x+y;
return;
}
(a)2
(b)3
(c)5
(d)Garbage value
(e)None of above
Output: (c)
Explanation:
_AX is register pseudo variable. It stores return type of function.
What is register pseudo variable?
What is global identifier?
(50) What will be output if you will compile and execute the following c code?
#define PRINT printf("c");printf("c++");
void main(){
float a=5.5;
if(a==5.5)
PRINT
else
printf("Not equal");
}
(a)c c++
(b)Not equal
(c)c
c++
(d)Compiler error
(e)None of above
Output: (d)
Explanation:
First see intermediate file:
try.c 1:
try.c 2: void main(){
try.c 3: float a=5.5;
try.c 4: if(a==5.5)
try.c 5: printf("c");printf("c++");
try.c 6: else
try.c 7: printf("Not equal");
try.c 8: }
try.c 9:
try.c 10:
If there are more than one statement in if block then it is necessary to write inside the { } otherwise it will show compiler error: misplaced else
More questions on preprocessors.
Preprocessor tutorial with examples.
Links to this post
5 comments
C questions and answer
(51) What will be output if you will compile and execute the following c code?
struct marks{
int p:3;
int c:3;
int m:2;
};
void main(){
struct marks s={2,-6,5};
printf("%d %d %d",s.p,s.c,s.m);
}
(a) 2 -6 5
(b) 2 -6 1
(c) 2 2 1
(d) Compiler error
(e) None of these
Answer: (c)
Explanation:
Binary value of 2: 00000010 (Select three two bit)
Binary value of 6: 00000110
Binary value of -6: 11111001+1=11111010
(Select last three bit)
Binary value of 5: 00000101 (Select last two bit)
Complete memory representation:
Structure tutorial
More questions
(52) What will be output if you will compile and execute the following c code?
void main(){
static char *s[3]={"math","phy","che"};
typedef char *( *ppp)[3];
static ppp p1=&s,p2=&s,p3=&s;
char * (*(*array[3]))[3]={&p1,&p2,&p3};
char * (*(*(*ptr)[3]))[3]=&array;
p2+=1;
p3+=2;
printf("%s",(***ptr[0])[2]);
}
(a) math
(b) phy
(c) che
(d) Compiler error
(e) None of these
Answer: (c)
Explanation:
Here
ptr: is pointer to array of pointer to string.
P1, p2, p3: are pointers to array of string.
array[3]: is array which contain pointer to array of string.
Pictorial representation:
Note: In the above figure upper part of box represent content and lower part represent memory address. We have assumed arbitrary address.
As we know p[i]=*(p+i)
(***ptr[0])[2]=(*(***ptr+0))[2]=(***ptr)[2]
=(***(&array))[2] //ptr=&array
=(**array)[2] //From rule *&p=p
=(**(&p1))[2] //array=&p1
=(*p1)[2]
=(*&s)[2] //p1=&s
=s[2]=”che”
How to read complex pointer?
Pointer tutorial.
(53) What will be output if you will compile and execute the following c code?
#include"conio.h"
int display();
int(*array[3])();
int(*(*ptr)[3])();
void main(){
array[0]=display;
array[1]=getch;
ptr=&array;
printf("%d",(**ptr)());
(*(*ptr+1))();
}
int display(){
int x=5;
return x++;
}
(a)5
(b)6
(c)0
(d)Compiler error
(e)None of these
Answer: (a)
Explanation:
In this example:
array []: It is array of pointer to such function which parameter is void and return type is int data type.
ptr: It is pointer to array which contents are pointer to such function which parameter is void and return type is int type data.
(**ptr)() = (** (&array)) () //ptr=&array
= (*array) () // from rule *&p=p
=array [0] () //from rule *(p+i)=p[i]
=display () //array[0]=display
(*(*ptr+1))() =(*(*&array+1))() //ptr=&array
=*(array+1) () // from rule *&p=p
=array [1] () //from rule *(p+i)=p[i]
=getch () //array[1]=getch
How to read complex array?
Array tutorial.
(54) What will be output if you will compile and execute the following c code?
void main(){
int i;
char far *ptr=(char *)0XB8000000;
*ptr='A';
*(ptr+1)=1;
*(ptr+2)='B';
*(ptr+3)=2;
*(ptr+4)='C';
*(ptr+5)=4;
}
Answer:
It output will be A, B and C in blue, green and red color respectively. As shown in following figure:
What is far pointer?
Advance c tutorial?
Working with text video memory.
(55) What will be output if you will compile and execute the following c code?
#include "dos.h"
void main(){
int j;
union REGS i,o;
char far *ptr=(char *)0XA0000000;
i.h.ah=0;
i.h.al=0x13;
int86(0x10,&i,&o);
for(j=1;j<=100;j++){
*(ptr+j)=4;
}
}
Answer:
One red color line in the graphics console as shown in the following figure
What is union REGS?
Advance c tutorial.
Working with graphics video memory.
(56) What will be output if you will compile and execute the following c code?
void main(){
int huge*p=(int huge*)0XC0563331;
int huge*q=(int huge*)0xC2551341;
*p=200;
printf("%d",*q);
}
(a)0
(b)Garbage value
(c)null
(d) 200
(e)Compiler error
Answer: (d)
Explanation:
Physical address of huge pointer p
Huge address: 0XC0563331
Offset address: 0x3331
Segment address: 0XC056
Physical address= Segment address * 0X10 + Offset address
=0XC056 * 0X10 +0X3331
=0XC0560 + 0X3331
=0XC3891
Physical address of huge pointer q
Huge address: 0XC2551341
Offset address: 0x1341
Segment address: 0XC255
Physical address= Segment address * 0X10 + Offset address
=0XC255 * 0X10 +0X1341
=0XC2550 + 0X1341
=0XC3891
Since both huge pointers p and q are pointing same physical address so content of q will also same as content of q.
What is huge pointer?
Pointer tutorial.
(57) Write c program which display mouse pointer and position of pointer.(In x coordinate, y coordinate)?
Answer:
#include”dos.h”
#include”stdio.h”
void main()
{
union REGS i,o;
int x,y,k;
//show mouse pointer
i.x.ax=1;
int86(0x33,&i,&o);
while(!kbhit()) //its value will false when we hit key in the key board
{
i.x.ax=3; //get mouse position
x=o.x.cx;
y=o.x.dx;
clrscr();
printf("(%d , %d)",x,y);
delay(250);
int86(0x33,&i,&o);
}
getch();
}
What is int86?
Advance c tutorial.
(58) Write a c program to create dos command: dir.
Answer:
Step 1: Write following code.
#include “stdio.h”
#include “dos.h”
void main(int count,char *argv[])
{
struct find_t q ;
int a;
if(count==1)
argv[1]="*.*";
a = _dos_findfirst(argv[1],1,&q);
if(a==0)
{
while (!a)
{
printf(" %s\n", q.name);
a = _dos_findnext(&q);
}
}
else
{
printf("File not found");
}
}
Step 2: Save the as list.c (You can give any name)
Step 3: Compile and execute the file.
Step 4: Write click on My computer of Window XP operating system and select properties.
Step 5: Select Advanced -> Environment Variables
Step 6: You will find following window:
Click on new button (Button inside the red box)
Step 7: Write following:
Variable name: path
Variable value: c:\tc\bin\list.c (Path where you have saved)
Step 8: Open command prompt and write list and press enter.
Command line argument tutorial.
(59) What will be output if you will compile and execute the following c code?
void main(){
int i=10;
static int x=i;
if(x==i)
printf("Equal");
else if(x>i)
printf("Greater than");
else
printf("Less than");
}
(a) Equal
(b) Greater than
(c) Less than
(d) Compiler error
(e) None of above
Answer: (d)
Explanation:
static variables are load time entity while auto variables are run time entity. We can not initialize any load time variable by the run time variable.
In this example i is run time variable while x is load time variable.
Properties of static variables.
Properties of auto variables.
(60) What will be output if you will compile and execute the following c code?
void main(){
int i;
float a=5.2;
char *ptr;
ptr=(char *)&a;
for(i=0;i<=3;i++)
printf("%d ",*ptr++);
}
(a)0 0 0 0
(b)Garbage Garbage Garbage Garbage
(c)102 56 -80 32
(d)102 102 -90 64
(e)Compiler error
Answer: (d)
Explanation:
In c float data type is four byte data type while char pointer ptr can point one byte of memory at a time.
Memory representation of float a=5.2
ptr pointer will point first fourth byte then third byte then second byte then first byte.
Content of fourth byte:
Binary value=01100110
Decimal value= 64+32+4+2=102
Content of third byte:
Binary value=01100110
Decimal value=64+32+4+2=102
Content of second byte:
Binary value=10100110
Decimal value=-128+32+4+2=-90
Content of first byte:
Binary value=01000000
Decimal value=64
Note: Character pointer treats MSB bit of each byte i.e. left most bit of above figure as sign bit.
How to represent float data type in memory?
(61) What will be output if you will compile and execute the following c code?
void main(){
int i;
double a=5.2;
char *ptr;
ptr=(char *)&a;
for(i=0;i<=7;i++)
printf("%d ",*ptr++);
}
(a) -51 -52 -52 -52 -52 -52 20 64
(b) 51 52 52 52 52 52 20 64
(c) Eight garbage values.
(d) Compiler error
(e) None of these
Answer: (a)
Explanation:
In c double data type is eight byte data type while char pointer ptr can point one byte of memory at a time.
Memory representation of double a=5.2
ptr pointer will point first eighth byte then seventh byte then sixth byte then fifth byte then fourth byte then third byte then second byte then first byte as shown in above figure.
Content of eighth byte:
Binary value=11001101
Decimal value= -128+64+8+4+1=-51
Content of seventh byte:
Binary value=11001100
Decimal value= -128+64+8+4=-52
Content of sixth byte:
Binary value=11001100
Decimal value= -128+64+8+4=-52
Content of fifth byte:
Binary value=11001100
Decimal value= -128+64+8+4=-52
Content of fourth byte:
Binary value=11001100
Decimal value= -128+64+8+4=-52
Content of third byte:
Binary value=11001100
Decimal value= -128+64+8+4=-52
Content of second byte:
Binary value=000010100
Decimal value=16+4=20
Content of first byte:
Binary value=01000000
Decimal value=64
Note: Character pointer treats MSB bit of each byte i.e. left most bit of above figure as sign bit.
How to represent double data type in memory?
(62) What will be output if you will compile and execute the following c code?
void main(){
printf("%s","c" "question" "bank");
}
(a) c question bank
(b) c
(c) bank
(d) cquestionbank
(e) Compiler error
Answer: (d)
Explanation:
In c string constant “xy” is same as “x” “y”
String tutorial.
(63) What will be output if you will compile and execute the following c code?
void main(){
printf("%s",__DATE__);
}
(a) Current system date
(b) Current system date with time
(c) null
(d) Compiler error
(e) None of these
Answer: (a)
Explanation:
__DATE__ is global identifier which returns current system date.
What is global identifier?
(64) What will be output if you will compile and execute the following c code?
void main(){
char *str="c-pointer";
printf("%*.*s",10,7,str);
}
(a) c-pointer
(b) c-pointer
(c) c-point
(d) cpointer null null
(e) c-point
Answer: (e)
Explanation:
Meaning of %*.*s in the printf function:
First * indicates the width i.e. how many spaces will take to print the string and second * indicates how many characters will print of any string.
Following figure illustrates output of above code:
Properties of printf function.
(65) What will be output if you will compile and execute the following c code?
void start();
void end();
#pragma startup start
#pragma exit end
int static i;
void main(){
printf("\nmain function: %d",++i);
}
void start(){
clrscr();
printf("\nstart function: %d",++i);
}
void end(){
printf("\nend function: %d",++i);
getch();
}
(a)
main function: 2
start function: 1
end function:3
(b)
start function: 1
main function: 2
end function:3
(c)
main function: 2
end function:3
start function: 1
(d) Compiler error
(e) None of these
Answer: (b)
Explanation:
Every c program start with main function and terminate with null statement. But #pragma startup can call function just before main function and #pragma exit
What is pragma directive?
Preprocessor tutorial.
(66) What will be output if you will compile and execute the following c code?
void main(){
int a=-12;
a=a>>3;
printf("%d",a);
}
(a) -4
(b) -3
(c) -2
(d) -96
(e) Compiler error
Answer :( c)
Explanation:
Binary value of 12 is: 00000000 00001100
Binary value of -12 wills 2’s complement of 12 i.e.
So binary value of -12 is: 11111111 11110100
Right shifting rule:
Rule 1: If number is positive the fill vacant spaces in the left side by 0.
Rule 2: If number is negative the fill vacant spaces in the left side by 1.
In this case number is negative. So right shift all the binary digits by three space and fill vacant space by 1 as shown following figure:
Since it is negative number so output will also a negative number but its 2’s complement.
Hence final out put will be:
And its decimal value is: 2
Hence output will be:-2
More questions on shifting operator.
Operator tutorial.
(67) What will be output if you will compile and execute the following c code?
#include "string.h"
void main(){
clrscr();
printf("%d %d",sizeof("string"),strlen("string"));
getch();
}
(a) 6 6
(b) 7 7
(c) 6 7
(d) 7 6
(e) None of these
Answer: (d)
Explanation:
Sizeof operator returns the size of string including null character while strlen function returns length of a string excluding null character.
String tutorial.
Library functions of string.
(68) What will be output if you will compile and execute the following c code?
void main(){
static main;
int x;
x=call(main);
clrscr();
printf("%d ",x);
getch();
}
int call(int address){
address++;
return address;
}
(a) 0
(b) 1
(c) Garbage value
(d) Compiler error
(e) None of these
Answer: (b)
Explanation:
As we know main is not keyword of c but is special type of function. Word main can be name variable in the main and other functions.
What is main function in c?
(69) What will be output if you will compile and execute the following c code?
void main(){
int a,b;
a=1,3,15;
b=(2,4,6);
clrscr();
printf("%d ",a+b);
getch();
}
(a) 3
(b) 21
(c) 17
(d) 7
(e) Compiler error
Answer: (d)
Explanation:
In c comma behaves as separator as well as operator.
a=1, 3, 15;
b= (2, 4, 6);
In the above two statements comma is working as operator. Comma enjoys least precedence and associative is left to right.
Assigning the priority of each operator in the first statement:
Hence 1 will assign to a.
Assigning the priority of each operator in the second statement:
Operator tutorial.
(70) What will be output if you will compile and execute the following c code?
int dynamic(int,...);
void main(){
int x,y;
x=dynamic(2,4,6,8,10,12,14);
y=dynamic(3,6,9,12);
clrscr();
printf("%d %d ",x,y);
getch();
}
int dynamic(int s,...){
void *ptr;
ptr=...;
(int *)ptr+=2;
s=*(int *)ptr;
return s;
}
(a) 8 12
(b) 14 12
(c) 2 3
(d) Compiler error
(e) None of these
Answer: (a)
Explanation:
In c three continuous dots is known as ellipsis which is variable number of arguments of function. In this example ptr is generic pointer which is pointing to first element of variable number of argument. After incrementing it will point third element.
What is variable number of argument?
(71) What will be output if you will compile and execute the following c code?
int extern x;
void main()
printf("%d",x);
x=2;
getch();
}
int x=23;
(a) 0
(b) 2
(c) 23
(d) Compiler error
(e) None of these
Answer: (c)
Explanation:
extern variables can search the declaration of variable any where in the program.
Properties of extern storage class.
(72) What will be output if you will compile and execute the following c code?
void main(){
int i=0;
if(i==0){
i=((5,(i=3)),i=1);
printf("%d",i);
}
else
printf("equal");
}
(a) 5
(b) 3
(c) 1
(d) equal
(e) None of above
Answer: (c)
Explanation:
Comma operator.
Operator tutorial.
(73) What will be output if you will compile and execute the following c code?
void main(){
int a=25;
clrscr();
printf("%o %x",a,a);
getch();
}
(a) 25 25
(b) 025 0x25
(c) 12 42
(d) 31 19
(e) None of these
Answer: (d)
Explanation:
%o is used to print the number in octal number format.
%x is used to print the number in hexadecimal number format.
Note: In c octal number starts with 0 and hexadecimal number starts with 0x.
What is octal number?
What is hexadecimal number?
(74) What will be output if you will compile and execute the following c code?
#define message "union is\
power of c"
void main(){
clrscr();
printf("%s",message);
getch();
}
(a) union is power of c
(b) union ispower of c
(c) union is
Power of c
(d) Compiler error
(e) None of these
Answer: (b)
Explanation:
If you want to write macro constant in new line the end with the character \.
Preprocessor tutorial.
(75) What will be output if you will compile and execute the following c code?
#define call(x) #x
void main(){
printf("%s",call(c/c++));
}
(a)c
(b)c++
(c)#c/c++
(d)c/c++
(e)Compiler error
Answer: (d)
Explanation:
# is string operator. It converts the macro function call argument in the string. First see the intermediate file:
test.c 1:
test.c 2: void main(){
test.c 3: printf("%s","c/c++");
test.c 4: }
test.c 5:
It is clear macro call is replaced by its argument in the string format.
What is # and ##?
Preprocessor tutorial?
(75) What will be output if you will compile and execute the following c code?
void main(){
if(printf("cquestionbank"))
printf("I know c");
else
printf("I know c++");
}
(a) I know c
(b) I know c++
(c) cquestionbankI know c
(d) cquestionbankI know c++
(e) Compiler error
Answer: (c)
Explanation:
Return type of printf function is integer which returns number of character it prints including blank spaces. So printf function inside if condition will return 13. In if condition any non- zero number means true so else part will not execute.
Prototype of printf function.
Links to this post
0 comments
for loop questions in c
(1)
void main(){
char i;
clrscr();
for(i=120;i<=128;i++){
printf("%d ",i);
}
getch();
}
Output: Infinite loop
(2)
void main(){
int i;
clrscr();
for(i=0,i++,i<=5;i++,i<=2;i=0,i<=5,i+=3){
printf("%d ",i);
}
getch();
}
Output: 2
(3)
void main(){
int i=1;
clrscr();
for(;;){
printf("%d ",i);
}
getch();
}
Output: Infinite loop
(4)
void main(){
int i=2;
clrscr();
for(i=0;i<=3;i++){
static int i;
i=i+8;
}
printf("%d",i);
getch();
}
Output: 4
(5)
extern int j;
void main(){
int i=0;
clrscr();
for(i=0;i<=2;i+=1){
int j=5;
printf("%d ",j);
j++;
}
getch();
}
int j=25;
Output: 5 5 5
(6)
extern int j;
void main(){
int i=0;
clrscr();
for(i=0;i<=2;i+=1){
int j=5;
printf("%d ",j);
j++;
}
getch();
}
int j=25;
Output: 5 5 5
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