/*
   testfunc07.cpp
   CIS 150
   6/9/2005
   David Klick
   
   This program demonstrates variable scope.
*/

#include <iostream>
using std::cout;

void changeXYZ(int n); // function prototype 

int w = 3;            // global variable
int y = 5;            // global variable

int main(void) {
   int x = 7;  // seen only within main
   int y = 9;  // seen only within main; hides global y
   int z = 11; // seen only within main

   // see what values are before function call
   cout << "Before calling changeXYZ: w=" << w
        << ", x=" << x << ", y=" << y << ", z="
        << z << '\n';

   changeXYZ(z);  // try to change values
   
   // see what values are after function call
   cout << "After calling changeXYZ:  w=" << w
        << ", x=" << x << ", y=" << y << ", z="
        << z << '\n';

   return 0;
}

/*
   Try to change x, y, and z values.
*/
void changeXYZ(int z) {
   int x = 2;  // must declare since main's x can't be seen here
   y = 4;      // changes global y
   z = 6;      // tries to change value of z
   cout << "Inside changeXYZ:         w=" << w
        << ", x=" << x << ", y=" << y << ", z="
        << z << '\n';
}

/*
   Sample output:
   
   Before calling changeXYZ: w=3, x=7, y=9, z=11
   Inside changeXYZ:         w=3, x=2, y=4, z=6
   After calling changeXYZ:  w=3, x=7, y=9, z=11
*/