funcptrtest.c

include <stdio.h>

const int b = 23;

// A normal function with an int parameter and void return type
void fun(int a)
{
  if (a < b)
    printf("Value of a (%d) is lesser then value of b (%d)\n", a, b);
  else if (a == b)
    printf("Value of a (%d) is equal value of b (%d)\n", a, b);
  else if (a > b)
    printf("Value of a (%d) is greater than value of b (%d)\n", a, b);
}

// main
int main(int argc, char **argv)
{
    int i = 0;
    /* fun_ptr is a pointer to function fun()
           void (*fun_ptr)(int) = &fun;
         is equivalent of following two
           void (*fun_ptr)(int);
           fun_ptr = &fun;
    */
    void (*fun_ptr)(int) = &fun;

    // call once with static int
    (*fun_ptr)(b);

    // iterate through for loop
    for (i = 1; i < 101; i+=11)  {
        // Invoking fun() using fun_ptr
        (*fun_ptr)(i);
    }

    return 0;
}