What does the & operator do when used with a variable?
Answer: B
The & (address-of) operator returns the memory address of the variable.
Q.162Easy
What is the output of the following code?
int x = 20;
int *p = &x;
printf("%d", *p);
Answer: B
The * operator dereferences the pointer p, accessing the value it points to, which is 20.
Q.163Easy
Which of the following is a void pointer?
Answer: B
void* is a generic pointer that can hold addresses of any data type and requires explicit typecasting when used.
Q.164Easy
What is the output of the following code?
int x = 5;
int *p = &x;
int q = &p;
printf("%d", q);
Answer: A
q is a pointer to pointer p. **q dereferences p twice, giving the value of x which is 5.
Q.165Easy
What will be the size of the pointer variable on a 64-bit system?
int *ptr;
Answer: B
On a 64-bit system, all pointers are 8 bytes regardless of the data type they point to.
Advertisement
Q.166Easy
What is the output?
int arr[] = {10, 20, 30};
int *p = arr;
printf("%d %d", *(p+1), arr[1]);
Answer: A
p+1 points to second element (20). arr[1] is also 20. Both print the same value.
Q.167Easy
What does void *ptr represent?
Answer: A
void* is a generic pointer. It can be cast to any other pointer type. No arithmetic can be done directly.
Q.168Easy
What is the output?
void swap(int *a, int *b) {
int temp = *a;
*a = *b;
*b = temp;
}
int x = 5, y = 10;
swap(&x, &y);
printf("%d %d", x, y);
Answer: B
swap() exchanges values through pointers. x becomes 10, y becomes 5 after function call.
Q.169Easy
What is the output?
char str[] = "ABC";
char *p = str;
printf("%c", *(p+2));
Answer: C
p+2 points to str[2] which is 'C'. Note: str[3] is null terminator.
Q.170Easy
What is the size of a pointer in a 64-bit system?
Answer: C
In 64-bit systems, pointers are 8 bytes (64 bits) regardless of the data type they point to.
Q.171Easy
How does free() handle a NULL pointer?
Answer: B
free(NULL) is safe in C and does nothing. This is by design to prevent errors when freeing pointers.
Q.172Easy
What is the result of: int x = 5; int *p = &x; int *q = p; if p == q?
Answer: B
Both p and q point to same address of x, so p == q evaluates to true (1).
Q.173Easy
What happens with: int arr[10]; int *p = arr; *p = 5; printf("%d", arr[0]);?
Answer: B
p points to arr[0]. *p = 5 modifies arr[0]. Printing arr[0] displays 5.
Q.174Easy
What is the output of the following code?
int x = 10;
int *p = &x;
int q = &p;
printf("%d", q);
Answer: A
q is a pointer to pointer p. **q dereferences q twice: first to get p, then to get the value of x which is 10.
Q.175Easy
Consider the declaration: const int *p; and int * const q;
Which statement is TRUE?
Answer: B
const int *p means p can change but the data it points to cannot. int * const q means q cannot change but the data it points to can be modified.
Q.176Easy
What is the primary issue with this code?
int *p;
*p = 10;
Answer: B
p is declared but not initialized to point to any valid memory location. Dereferencing an uninitialized pointer causes undefined behavior.
Q.177Easy
What is the primary difference between a structure and a union in C?
Answer: A
In structures, each member gets its own memory space. In unions, all members share the same memory location, so only one member can hold a value at a time.
Q.178Easy
What will be the output of sizeof(union test) if union has members: int a, char b, float c?
Answer: A
Union size equals the size of its largest member. Here, both int and float are 4 bytes (largest), so sizeof(union test) = 4 bytes.
Q.179Easy
Which keyword is used to define a structure in C?
Answer: B
The 'struct' keyword is used to define structures in C. 'class' is used in C++ and Java.
Q.180Easy
What is the size of the following structure?
struct point { int x; int y; float z; };
Answer: B
int x = 4 bytes, int y = 4 bytes, float z = 4 bytes. Total = 12 bytes (no padding in this case on most systems).
