C++ Custom Routines

C++ is a hybrid language and as such offers global functions and class methods. A function must come before it's usage or you can prototype the function.

Prototyping

The following is the complete C++ source code for a simple console application that demonstrates prototyping.

You either have to define your custom routines above main() so that they can be used within main() or prototype them. C++ allows you to prototype custom routines so that you can put their implementation below main.

#include "stdafx.h"
#include <iostream>
#include <string>

using namespace std;

//
//Prototypes
//
void sayHello(string pName);
int add(int p1, int p2);

//
//Main.
//
void main()
{
  sayHello("Mike");
  cout << "2+2=" << add(2,2) << "\n";
}

//
//Implementation section.
//
void sayHello(string pName) {
  cout << "Hello " + pName + "\n";
}

int add(int p1, int p2) {
  int result;

  result = p1 + p2;
  return result;
}