如何在java中循环某些内容？

Question

我正在为我的班级编写一个程序，但我似乎不太明白如何循环它。所以我还没有完全了解循环的变化，我想看看一个例子，我如何添加一个循环来重复运行这个程序，除非输入999

javax.swing.JOptionPane;

public class Evan {

public static void main (String[]args) {


String input1= JOptionPane.showInputDialog("Enter a evan number");
int num1 = Integer.parseInt( input1);


if (num1==999)
    System.exit(num1);

if ( (num1%2) == 0 ) 
System.out.println("Good Job!");

else  {
    System.out.println("HEY thats not evan try again");

}

    }
}

Answer 1

用while (true)包围代码中应该重复的部分，这使它永远继续下去（虽然System.exit(num1)仍将退出，但您可能应该用break;替换它）

while (true) {
    String input1= JOptionPane.showInputDialog("Enter a evan number");
    int num1 = Integer.parseInt( input1);


    if (num1==999)
        System.exit(num1);

    if ( (num1%2) == 0 ) 
    System.out.println("Good Job!");

    else  {
        System.out.println("HEY thats not evan try again");

    }
}

Answer 2

最好暂时使用正确的条件

  Integer num1 = 0;
  while (num1 != 999) {
     String input1= JOptionPane.showInputDialog("Enter a evan number");
     num1 = Integer.parseInt( input1);

     if ( (num1%2) == 0 ) 
       System.out.println("Good Job!");

    else  {
       System.out.println("HEY thats not evan try again");
    }
}
System.exit(num1);