while

  While 循环控制

 

  while(布尔表达式){

       //循环体

  }

 

  Scanner console = new Scanner(System.in);

  while(true){

      qty = console.nextInt();

      if(qty>0 && qty<=5){            //五个以内

        break;                        //打断, 打断当前循环

      }

  }