#include<iostream>
using namespace std;

int foo();

int main()
{
	cout << foo() << endl;
	cout << foo() << endl;
	cout << foo() << endl;

	return 0;
}

int foo()
{
	//int i = 0;      //Variable i will be initialized every time the function is called. 
	static int i = 0;  //Variable i will be initialized at the first time and the value of i stays for next function call. 
	i++;

	return i;
}