#include <iostream>
#include <conio.h>
using namespace std;

bool redo();

int main()
{
    top:
    cout << "Hello, world!\n";
    redo();
    if(redo())
    goto top;
}

bool redo()
{
    cout << "Do again? [y/n] (n)\n";
    char ch;
    if( !_kbhit() ){
    ch = getch();
    if(ch == 121)
    return true;
    else
    return false;}
}