我将如何使用 while 循环来继续请求用户输入

Question

我用 while 循环尝试了几件事，但似乎无法让它工作。我想一直请求用户输入，直到用户输入数字 0，这是我到目前为止的代码：

import java.util.*;

public class Task10 {

    public static void main(String[] args) {
        System.out.println("Enter a year to check if it is a leap year");
        Scanner input = new Scanner(System.in);
        int year = input.nextInt();

        if ((year % 4 == 0) || ((year % 400 == 0) && (year % 100 != 0)))
            System.out.println(year + " is a leap year");
        else
            System.out.println(year + " is not a leap year");
    }
}

Answer 1

在输入行上方使用 while 循环：

 while(true)

并且，使用if 条件到break。

if(year == 0)
    break;

另外，leap year 的条件在您的代码中是错误的。应该是：

if((year % 100 == 0 && year % 400 == 0) || (year % 4 == 0 && year % 100 != 0))
    //its a leap year
else
    //its not

PS：和cmets一样，我给出一个完整的代码：

import java.util.*;

public class Task10 {

public static void main(String[] args) {
    System.out.println("Enter a year to check if it is a leap year");
    while(true){
    Scanner input = new Scanner(System.in);
        int year = input.nextInt();
        if(year == 0)
            break;
        if((year % 100 == 0 && year % 400 == 0) || (year % 4 == 0 && year % 100 != 0))
            System.out.println(year + " is a leap year");
        else
            System.out.println(year + " is not a leap year");
    }
}

}

Answer 2

您需要做一些事情来保持输入循环运行，直到遇到停止条件（在您的情况下，当用户输入 0 时）

// First get the scanner object with the input stream
Scanner sc = new Scanner(System.in); 

// Just using do-while here for no reason, you can use a simple while(true) as well
do{
    int input = sc.nextInt();  // read the next input
    if (int == 0) { // check if we need to exit out
        // break only if 0 is entered, this means we don't want to run the loop anymore
        break;
    } else {
        // otherwise, do something with the input
    }
} while(true); // and keep repeating

Answer 3

您应该将输入代码放在一个while循环中并执行while循环，直到年份为0或更小。

public static void main(String[] args) {
        int year = 1;
        while(year > 0)
        {
            System.out.println("Enter a year to check if it is a leap year");
            Scanner input = new Scanner(System.in);
            year = input.nextInt();
            if ((year % 4 == 0) || ((year % 400 == 0) && (year % 100 != 0)))
                System.out.println(year + " is a leap year");
            else
                System.out.println(year + " is not a leap year");
        }


    }