Interview Questions
- What is Wild Pointer in C
- What is pointer to a function in C
What is Wild pointer in C
A Pointer in C that has not been initialized till its first use is known as Wild pointer. A wild pointer points to some random memory location.
int main() {
int *ptr;
/* Ptr is a wild pointer, as it is not initialized Yet */
printf("%d", *ptr);
}
How can we avoid Wild Pointers ?
We can initialize a pointer at the point of declaration wither by the address of some object/variable or by NULL;
int main() {
int val = 5;
int *ptr = &val; /* Initializing pointer */
/* Ptr is not a wild pointer, it is pointing to the address of variable val */
printf("%d", *ptr);
}
What is pointer to a function in C
A pointer to a function is a pointer that stores the address of a function. Unlike regular pointers, function pointers points to code not to memory location where data is stored. We can use a function pointer to call a function which it is pointing to. Here is the Syntax and Example of function pointer.
C program to call a function using function pointer
#include <stdio.h>
int getSum(int a, int b){
return a + b;
}
int main() {
int sum;
/* f_ptr is a pointer to function which takes
two integer as input and returns an integer.
We can use addressof operator to get the base
address of any function. */
int (*f_ptr)(int, int) = &getSum;
/* Now, calling getSum function using f_ptr */
sum = (*f_ptr)(2, 5);
printf("%d\n", sum);
return 0;
}
Output
7
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