fgeek- storage-modifier ---Storage Classes and Type Qualifiers

Storage Classes and Type Qualifiers

Question 1 WRONG

Which of the following is not a storage class specifier in C?

A	auto
B	register
C	static
D	extern
	volatile
	typedef

Discuss it

Question 1 Explanation: 

volatile is not a storage class specifier. volatile and const are type qualifiers.

Question 4 CORRECT

#include <stdio.h> int main() {     int x = 5;     int * const ptr = &x;     ++(*ptr);     printf("%d", x);         return 0; }

A	Compiler Error
B	Runtime Error
	6
D	5

Discuss it

Question 4 Explanation: 

See following declarations to know the difference between constant pointer and a pointer to a constant. int * const ptr —> ptr is constant pointer. You can change the value at the location pointed by pointer p, but you can not change p to point to other location. int const * ptr —> ptr is a pointer to a constant. You can change ptr to point other variable. But you cannot change the value pointed by ptr. Therefore above program works well because we have a constant pointer and we are not changing ptr to point to any other location. We are only icrementing value pointed by ptr.

Question 5 WRONG

#include <stdio.h> int main() {     int x = 5;     int const * ptr = &x;     ++(*ptr);     printf("%d", x);         return 0; }

	Compiler Error
B	Runtime Error
	6
D	5

Discuss it

Question 5 Explanation: 

See following declarations to know the difference between constant pointer and a pointer to a constant. int * const ptr —> ptr is constant pointer. You can change the value at the location pointed by pointer p, but you can not change p to point to other location. int const * ptr —> ptr is a pointer to a constant. You can change ptr to point other variable. But you cannot change the value pointed by ptr. In the above program, ptr is a pointer to a constant. So the value pointed cannot be changed.

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