FunctionPointerFun.c

#include <stdio.h>

struct fn_struct {
    int number;
    void (*f) (void *);
};

void foo (unsigned int m)
{
    unsigned int tmp = 0;
    while (tmp++ < m)
        puts ("foo function");
}

void bar (char *words)
{
    puts (words);
}

int main (int argc, char *argv[])
{
    // Note compound literals have auto storage duration.
    struct fn_struct *fn_ptr =
        &(struct fn_struct){ .number = 1,
                             .f = (void (*) (void *))bar };

    (*(void (*) (char *))fn_ptr->f) ("hello world");

    fn_ptr->f = (void (*) (void *))foo;

    (*(void (*) (unsigned int))fn_ptr->f) (3);

    return 0;
}