C++ global variables

#include <iostream>
using namespace std;
#include <conio.h>        //for getch()
char ch = 'a';            //global variable ch
void getachar();/*  w ww.jav  a 2  s . c o m*/
void putachar();
int main()
{
   while( ch != '\r' )    //main() accesses ch
   {
      getachar();
      putachar();
   }
   cout << endl;
   return 0;
}
void getachar()           //getachar() accesses ch
{
   ch = getch();
}
void putachar()           //putachar() accesses ch
{
   cout << ch;
}

#include <iostream>
using namespace std;
int g, h;     // Global because they're defined before a function.
int main()//from w  w w.  j  av a  2  s.co  m
{
   // int main()'s code goes here.
}