Saturday, 17 August 2013
Sunday, 4 August 2013
C PROGRAMMING QUESTIONS AND ANSWER contin..
(10) What will be output if you will compile and
execute the following c code?
#include<stdio.h>
#include <string.h>
int main(){
printf("%d %d",sizeof("string"),strlen("string"));
return 0;
}
(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.
(11) What will be output if you will compile and
execute the following c code?
#include<stdio.h>
int main(){
static main;
int x;
x=call(main);
printf("%d ",x);
return 0;
}
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.
(12) What will be output if you will compile and
execute the following c code?
#include<stdio.h>
int main(){
int a,b;
a=1,3,15;
b=(2,4,6);
printf("%d ",a+b);
return 0;
}
(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:
(13) What will be output if you will compile and
execute the following c code?
#include<stdio.h>
int extern x;
int main()
printf("%d",x);
x=2;
return 0;
}
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
anywhere in the program.
(14) What will be output if you will compile and
execute the following c code?
#include<stdio.h>
int 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)
(15) What will be output if you will compile and
execute the following c code?
int main(){
int a=25;
printf("%o %x",a,a);
return 0;
}
(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.
(16) What will be output if you will compile and
execute the following c code?
#include<stdio.h>
#define message "union is\
power of c"
int main(){
printf("%s",message);
return 0;
}
(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 \.
(17) What will be output if you will compile and
execute the following c code?
#include<stdio.h>
#define call(x) #x
int main(){
printf("%s",call(c/c++));
return 0;
}
(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: return 0;
test.c 4: }
test.c 5:
It is clear macro call is replaced by its argument in
the string format.
(18) What will be output if you will compile and
execute the following c code?
#include<stdio.h>
int main(){
if(printf("cquestionbank"))
else
return 0;
}
(a) I know c
(b) I know c++
(c) cquestionbankI know c
(d) cquestionbankI know c++
(e) Compiler error
Answer: (c)
Explanation:
printf("I know c");
printf("I know c++");
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.
(19) What will be output if you will compile and
execute the following c code?
#include<stdio.h>
int main(){
int i=10;
static int x=i;
if(x==i)
else if(x>i)
else
return 0;
}
(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 cannot initialize any
load time variable by the run time variable.
In this example i is run time variable while x is load
time variable.
printf("Equal");
printf("Greater than");
printf("Less than");
(20) What will be output if you will compile and
execute the following c code?
#include<stdio.h>
int main(){
printf("%s",__DATE__);
return 0;
}
(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.
(21) What will be output if you will compile and
execute the following c code?
#include<stdio.h>
void start();
void end();
#pragma startup start
#pragma exit end
int static i;
int main(){
printf("\nmain function: %d",++i);
return 0;
}
void start(){
printf("\nstart function: %d",++i);
}
void end(){
printf("\nend function: %d",++i);
}
(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
execute the following c code?
#include<stdio.h>
#include <string.h>
int main(){
printf("%d %d",sizeof("string"),strlen("string"));
return 0;
}
(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.
(11) What will be output if you will compile and
execute the following c code?
#include<stdio.h>
int main(){
static main;
int x;
x=call(main);
printf("%d ",x);
return 0;
}
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.
(12) What will be output if you will compile and
execute the following c code?
#include<stdio.h>
int main(){
int a,b;
a=1,3,15;
b=(2,4,6);
printf("%d ",a+b);
return 0;
}
(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:
(13) What will be output if you will compile and
execute the following c code?
#include<stdio.h>
int extern x;
int main()
printf("%d",x);
x=2;
return 0;
}
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
anywhere in the program.
(14) What will be output if you will compile and
execute the following c code?
#include<stdio.h>
int 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)
(15) What will be output if you will compile and
execute the following c code?
int main(){
int a=25;
printf("%o %x",a,a);
return 0;
}
(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.
(16) What will be output if you will compile and
execute the following c code?
#include<stdio.h>
#define message "union is\
power of c"
int main(){
printf("%s",message);
return 0;
}
(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 \.
(17) What will be output if you will compile and
execute the following c code?
#include<stdio.h>
#define call(x) #x
int main(){
printf("%s",call(c/c++));
return 0;
}
(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: return 0;
test.c 4: }
test.c 5:
It is clear macro call is replaced by its argument in
the string format.
(18) What will be output if you will compile and
execute the following c code?
#include<stdio.h>
int main(){
if(printf("cquestionbank"))
else
return 0;
}
(a) I know c
(b) I know c++
(c) cquestionbankI know c
(d) cquestionbankI know c++
(e) Compiler error
Answer: (c)
Explanation:
printf("I know c");
printf("I know c++");
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.
(19) What will be output if you will compile and
execute the following c code?
#include<stdio.h>
int main(){
int i=10;
static int x=i;
if(x==i)
else if(x>i)
else
return 0;
}
(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 cannot initialize any
load time variable by the run time variable.
In this example i is run time variable while x is load
time variable.
printf("Equal");
printf("Greater than");
printf("Less than");
(20) What will be output if you will compile and
execute the following c code?
#include<stdio.h>
int main(){
printf("%s",__DATE__);
return 0;
}
(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.
(21) What will be output if you will compile and
execute the following c code?
#include<stdio.h>
void start();
void end();
#pragma startup start
#pragma exit end
int static i;
int main(){
printf("\nmain function: %d",++i);
return 0;
}
void start(){
printf("\nstart function: %d",++i);
}
void end(){
printf("\nend function: %d",++i);
}
(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
C PROGRAMMING QUESTIONS AND ANSWER contin..
(6) What will be output if you will compile and execute
the following c code?
#include<stdio.h>
int main(){
int i;
double a=5.2;
char *ptr;
ptr=(char *)&a;
for(i=0;i<=7;i++)
return 0;
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.
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.
(7) What will be output if you will compile and execute
the following c code?
#include<stdio.h>
int main(){
printf("%s","c" "question" "bank");
return 0;
}
(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”
(8) What will be output if you will compile and execute
the following c code?
#include<stdio.h>
int main(){
char *str="c-pointer";
printf("%*.*s",10,7,str);
return 0;
}
(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:
(9) What will be output if you will compile and
execute the following c code?
#include<stdio.h>
int main(){
int a=-12;
a=a>>3;
printf("%d",a);
return 0;
}
(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.
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.
And its decimal value is: 2
Hence output will be:-2
the following c code?
#include<stdio.h>
int main(){
int i;
double a=5.2;
char *ptr;
ptr=(char *)&a;
for(i=0;i<=7;i++)
return 0;
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.
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.
(7) What will be output if you will compile and execute
the following c code?
#include<stdio.h>
int main(){
printf("%s","c" "question" "bank");
return 0;
}
(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”
(8) What will be output if you will compile and execute
the following c code?
#include<stdio.h>
int main(){
char *str="c-pointer";
printf("%*.*s",10,7,str);
return 0;
}
(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:
(9) What will be output if you will compile and
execute the following c code?
#include<stdio.h>
int main(){
int a=-12;
a=a>>3;
printf("%d",a);
return 0;
}
(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.
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. And its decimal value is: 2Hence output will be:-2
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