Role-specific C Pointers Interview Questions & Answers:

There are times when it's necessary to have a pointer that doesn't point to anything. The macro NULL, defined in <stddef.h>, has a value that's guaranteed to be different from any valid pointer. NULL is a literal zero, possibly cast to void* or char*. Some people, notably C++ programmers, prefer to use 0 rather than NULL.<stddef.h>

2. Explain void pointer?

A void pointer is a C convention for "a raw address." The compiler has no idea what type of object a void pointer "really points to." If you write
int *ip;
ip points to an int. If you write
void *p;
p doesn't point to a void!

3. The operator used to get value at address stored in a pointer variable is
A. *
B. &
C. &&
D. ||

Option A
(*)

4. A pointer is

A. A keyword used to create variables
B. A variable that stores address of an instruction
C. A variable that stores address of other variable
D. All of the above

Option C
(A variable that stores address of other variable)

5. What would be the equivalent pointer expression for referring the array element a[i][j][k][l]

A. ((((a+i)+j)+k)+l)
B. *(*(*(*(a+i)+j)+k)+l)
C. (((a+i)+j)+k+l)
D. ((a+i)+j+k+l)

Option B
*(*(*(*(a+i)+j)+k)+l)

6. If a variable is a pointer to a structure, then which of the following operator is used to access data members of the structure through the pointer variable?
A. .
B. &
C. *
D. ->

Option D
(->)

7. How many bytes are occupied by near, far and huge pointers (DOS)?

A. near=2 far=4 huge=4
B. near=4 far=8 huge=8
C. near=2 far=4 huge=8
D. near=4 far=4 huge=8

Option A
(near=2 far=4 huge=4)

8. In which header file is the NULL macro defined?

A. stdio.h
B. stddef.h
C. stdio.h and stddef.h
D. math.h

Option C
(stdio.h and stddef.h)