从0学Java之While循环

//初始化
    Scanner in = new Scanner(System.in);
    //读入投币金额
    System.out.println("请投币：");
    int balance = 0;
    
    while(true)
    {
      
    int amount = in.nextInt();
    balance =balance+amount ;
    if(balance >= 4)
    {
    //打印购物小票
    System.out.println("*****************");
    System.out.println("*   可口可乐   *");
    System.out.println("*    一罐     *");
    System.out.println("*  售价：4元  *");
    System.out.println("*****************");
    
    // 计算并打印找零
    System.out.println("找零：" + (balance-4));
    }
    else  
    {
    System.out.println("请继续投币：");  
      }
    }