/*File:  Functions05.cpp

This C++ program illustrates a function with
a parameter and a return value.

This program displays the following text on the 
screen:

a = 2
a doubled = 4

************************************************/

#include <iostream>
using namespace std;

int doubleIt(int x){
  return x + x;
}//end doubleIt
//---------------------------------------------//

int main(){//Global main function.
  int a = 2;
  cout << "a = " << a << endl;
  cout << "a doubled = " << doubleIt(a) << endl;
  return 0;
}//end main function

Listing 5