#include <iostream> using namespace std ; void my_test_function(void) ; // global variable // usually a very bad idea int my_test_number = 0 ; int main () { cout << my_test_number << endl ; my_test_function() ; cout << my_test_number << endl ; return 0 ; } void my_test_function(void) { int my_test_number = 1; cout << my_test_number << endl; }