Function Pointer in C

C Programming Language Pointer in C Language (Article) Pointer in C Language (Program)

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Program:

#include <stdio.h>
// A normal function with an int parameter
// and void return type
void fun(int a)
{
    printf("Value of a is %d\n", a);
}
 
int main()
{
    // fun_ptr is a pointer to function fun() 
    void (*fun_ptr)(int) = &fun;
 
    /* The above line is equivalent of following two
       void (*fun_ptr)(int);
       fun_ptr = &fun; 
    */
 
    // Invoking fun() using fun_ptr
    (*fun_ptr)(10);
 
    return 0;
}

Output:

Value of a is 10

Explanation:

Why do we need an extra bracket around function pointers like fun_ptr in above example? If we remove bracket, then the expression “void (*fun_ptr)(int)” becomes “void *fun_ptr(int)” which is declaration of a function that returns void pointer.

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