C Programming Questions and Answers on Pointers to Functions for Freshers

1. Which function is not called in the following program?

1.     #include 

2.     void first()

3.     {

4.         printf("first");

5.     }

6.     void second()

7.     {

8.         first();

9.     }

10.     void third()

11.     {

12.         second();

13.     }

14.     void main()

15.     {

16.         void (*ptr)();

17.         ptr = third;

18.         ptr();

19.     }

a) Function first
b) Function second
c) Function third
d) None of the mentioned

Answer: d

2. How to call a function without using the function name to send parameters?

a) typedefs
b) Function pointer
c) Both typedefs and Function pointer
d) None of the mentioned

Answer: b

3. Correct syntax to pass a Function Pointer as an argument

a) void pass(int (*fptr)(int, float, char)){}
b) void pass(*fptr(int, float, char)){}
c) void pass(int (*fptr)){}
d) void pass(*fptr){}

Answer: a

4. Which of the following is not possible in C?

a) Array of function pointer
b) Returning a function pointer
c) Comparison of function pointer
d) None of the mentioned

Answer: d

5. What is the output of this C code?

1.     #include 

2.     void first()

3.     {

4.         printf("Hello World");

5.     }

6.     void main()

7.     {

8.         void *ptr() = first;

9.         ptr++

10.         ptr();

11.     }

a) Illegal application of ++ to void data type
b) pointer function initialized like a variable
c) Illegal application of ++ to void data type & pointer function initialized like a variable
d) None of the mentioned

Answer: c

6. What is the output of this C code?

1.     #include 

2.     int mul(int a, int b, int c)

3.     {

4.         return a * b * c;

5.     }

6.     void main()

7.     {

8.         int (*function_pointer)(int, int, int);

9.         function_pointer  =  mul;

10.         printf("The product of three numbers is:%d",

11.         function_pointer(2, 3, 4));

12.     }

a) The product of three numbers is:24
b) Run time error
c) Nothing
d) Varies

Answer: a

7. What is the output of this C code?

1.     #include 

2.     int mul(int a, int b, int c)

3.     {

4.         return a * b * c;

5.     }

6.     void main()

7.     {

8.         int (function_pointer)(int, int, int);

9.         function_pointer = mul;

10.         printf("The product of three numbers is:%d",

11.         function_pointer(2, 3, 4));

12.     }

a) The product of three numbers is:24
b) Compile time error
c) Nothing
d) Varies

Answer: b

8. What is the output of this C code?

1.     #include 

2.     void f(int (*x)(int));

3.     int myfoo(int);

4.     int (*fooptr)(int);

5.     int ((*foo(int)))(int);

6.     int main()

7.     {

8.         fooptr = foo(0);

9.         fooptr(10);

10.     }

11.     int ((*foo(int i)))(int)

12.     {

13.         return myfoo;

14.     }

15.     int myfoo(int i)

16.     {

17.         printf("%d\n", i + 1);

18.     }

a) 10
b) 11
c) Compile time error
d) Undefined behaviour

Answer: b

9. What is the output of this C code?

1.     #include 

2.     int mul(int a, int b, int c)

3.     {

4.         return a * b * c;

5.     }

6.     void main()

7.     {

8.         int *function_pointer;

9.         function_pointer = mul;

10.         printf("The product of three numbers is:%d",

11.         function_pointer(2, 3, 4));

12.     }

a) The product of three numbers is:24
b) Compile time error
c) Nothing
d) Varies

Answer: b

10. What is the output of this C code?

1.     #include 

2.     int sub(int a, int b, int c)

3.     {

4.         return a - b - c;

5.     }

6.     void main()

7.     {

8.         int (*function_pointer)(int, int, int);

9.         function_pointer = ⊂

10.         printf("The difference of three numbers is:%d",

11.         (*function_pointer)(2, 3, 4));

12.     }

a) The difference of three numbers is:1
b) Run time error
c) The difference of three numbers is:-5
d) Varies

Answer: c

11. One of the uses for function pointers in C is
a) Nothing
b) There are no function pointers in c
c) To invoke a function
d) To call a function defined at run-time.

Answer: d

12. What is the output of this C code?

1.     #include 

2.     void f(int);

3.     void (*foo)() = f;

4.     int main(int argc, char *argv[])

5.     {

6.         foo(10);

7.         return 0;

8.     }

9.     void f(int i)

10.     {

11.         printf("%d\n", i);

12.     }

a) Compile time error
b) 10
c) Undefined behaviour
d) None of the mentioned

Answer: b

13. What is the output of this C code?

1.     #include 

2.     void f(int);

3.     void (*foo)(void) = f;

4.     int main(int argc, char *argv[])

5.     {

6.         foo(10);

7.         return 0;

8.     }

9.     void f(int i)

10.     {

11.         printf("%d\n", i);

12.     }

a) Compile time error
b) 10
c) Undefined behaviour
d) None of the mentioned

Answer: a

14. What is the output of this C code?

1.     #include 

2.     void f(int);

3.     void (*foo)(float) = f;

4.     int main()

5.     {

6.         foo(10);

7.     }

8.     void f(int i)

9.     {

10.         printf("%d\n", i);

11.     }

a) Compile time error
b) 10
c) 10.000000
d) Undefined behaviour

Answer: d

15. What is the output of this C code?

1.     #include 

2.     void f(int (*x)(int));

3.     int myfoo(int i);

4.     int (*foo)(int) = myfoo;

5.     int main()

6.     {

7.         f(foo(10));

8.     }

9.     void f(int (*i)(int))

10.     {

11.         i(11);

12.     }

13.     int myfoo(int i)

14.     {

15.         printf("%d\n", i);

16.         return i;

17.     }

a) Compile time error
b) Undefined behaviour
c) 10 11
d) 10 Segmentation fault

Answer: d

16. What is the output of this C code?

1.     #include 

2.     void f(int (*x)(int));

3.     int myfoo(int);

4.     int (*foo)() = myfoo;

5.     int main()

6.     {

7.         f(foo);

8.     }

9.     void f(int(*i)(int ))

10.     {

11.         i(11);

12.     }

13.     int myfoo(int i)

14.     {

15.         printf("%d\n", i);

16.         return i;

17.     }

a) 10 11
b) 11
c) 10
d) Undefined behaviour

Answer: b