/* Filename:  params.cpp

   Author:  Br. David Carlson

   Date:  January 13, 1998

   Revised:  July 20, 2000; November 21, 2001

   This program illustrates some features of parameter passing.

   Tested with:
      Microsoft Visual C++ 6.0
      Microsoft Visual C++ .NET
      g++ under Linux
*/

#include <iostream>
using namespace std;


// Global variable (usually best to avoid these):

int num;


// Function prototypes:

int calc(int & x, int y);

void compute(int b);


int main(void)
   {
   int a, b, ans;

   ans = 1;
   num = 2;
   a = 3;
   b = 4;
   ans = calc(a, b);
   cout << "main -- values of a, b, ans, num: " <<
      a << " " << b << " " << ans << " " << num << endl;
   compute(b);
   cout << "main -- values of a, b, ans, num: " <<
      a << " " << b << " " << ans << " " << num << endl;

   return 0;
   }


int calc(int & x, int y)
   {
   int c;

   x++;   // shorthand for x = x + 1
   y--;   // shorthand for y = y - 1
   c = x + 2 * y;
   cout << "calc -- values of x, y, c, num: " <<
      x << " " << y << " " << c << " " << num << endl;
   return c;
   }


void compute(int b)
   {
   b = b + 10;
   num = 37;
   cout << "compute -- values of b, num: " << b << " " << num << endl;
   }