#include <stdio.h>
 
 
void something()
{
    printf("hello\n");
}
 
 
void somethingElse()
{
    printf("hello2\n");
}
 
int main(void)
{
   (void)(*pointer)() = something;
 
   pointer();
 
   pointer = somethingElse;
 
   pointer();
 
    return 0;
}

 
 
#include <iostream>
#include <string>
 
using std::string;
using std::cout;
 
//simple function
void print(string _name) { std::cout<<"Hello"<<_name; }
 
//another function with return type int.
int cal_pay(double _pay,int _hours) 
{
    return (2*_pay + 1000)*_hours;
}
 
//function pointer of the same type i.e. complete function type must match exactly
void (*pfct)(string);   //check the return type and arguments   
int (*cfct)(double,int);
int main() 
{
     pfct=&print;             //pfct points to print function
     pfct("Laiq");
 
     cfct=cal_pay            //also o.k. same as &cal_pay
     int ans = (*cfct)(500.00,4);    //another way of calling 
     return 0;
}