“If”语句不会循环打印

Question

我的代码有效，只有一个问题。 该代码旨在打印两个用户输入之间的数字。 代码的那部分有效，但是如果第一个数字大于第二个数字，则意味着不再打印并再次询问。 到目前为止一切正常，但是如果第一个数字大于第二个，控制台和代码就结束了，我不知道为什么？ 你们能帮忙解释一下我做错了什么吗？ 谢谢！ 这是我的代码：

public static void main(String[] args) {
    Scanner reader = new Scanner(System.in);

    int higherNum, lowerNum;

    System.out.print("First: ");
    lowerNum=Integer.parseInt(reader.nextLine());

    System.out.print("Second: ");
    higherNum=Integer.parseInt(reader.nextLine());

    while (higherNum>=lowerNum){
        if (lowerNum>higherNum){
            System.out.print("Sorry, you put your first number higher than your second, please make your first number a smaller number than your second. "); // this does not print 
        }
    }

    System.out.println(lowerNum++);
}

Answer 1

您的循环仅在 highNum >=lowerNum 时开始，这意味着循环内的 if 条件永远不会为真。

要实现您的输出，您应该执行以下操作。

while (lowerNum>higherNum ){
            System.out.print("Sorry, you put your first number higher than your second,   please make your first number a smaller number than your second. "); // this does not print

            System.out.print("First: ");
            lowerNum=Integer.parseInt(reader.nextLine());

            System.out.print("Second: ");
            higherNum=Integer.parseInt(reader.nextLine());

        }

        while(lowerNum <= higherNum) {
            System.out.println(lowerNum++);
        }

Answer 2

我建议您先使用 if 条件：

if (lowerNum>higherNum){
    System.out.print("Sorry, you put your first number higher than your second, please make your first number a smaller number than your second. ");
} else{
    while (higherNum>=lowerNum){
        System.out.println(lowerNum++);
    }
}

发生这种情况是因为如果lowerNum大于higherNum您的while 条件将导致false 并且不会打印任何内容，因为错误消息在while 循环内。

Answer 3

你的 if 应该在 while 之前。 我在路上修了一些其他的东西。

public static void main(String[] args) {

    Scanner reader = new Scanner(System.in);
    int higherNum = 0, lowerNum = 1;

    while(lowerNum>=higherNum){

        System.out.print("First: ");
        lowerNum=Integer.parseInt(reader.nextLine());

        System.out.print("Second: ");
        higherNum=Integer.parseInt(reader.nextLine());

        if(lowerNum>=higherNum){

            System.out.println("Sorry, you put your first number higher than your second, please make your first number a smaller number than your second. ");

        } else {

            while(lowerNum<higherNum-1){
                System.out.println(++lowerNum);
            }

        }
    }
}

Answer 4

您可以使用重新启动过程的方法提供数字输入。 递归选项将有助于解决该问题。

public void TakeNumbers(){ Scanner reader = new Scanner(System.in);

int higherNum, lowerNum;

System.out.print("First: ");
lowerNum=Integer.parseInt(reader.nextLine());

System.out.print("Second: ");
higherNum=Integer.parseInt(reader.nextLine());

 if (lowerNum>higherNum){
        System.out.print("Sorry, you put your first number higher than your second, please make your first number a smaller number than your second. ");

TakeNumbers();

System.out.println(lowerNum++);

}

公共静态无效主（字符串 [] args）{

TakeNumbers();

}

Answer 5

是的，它会在 for 循环内打印以进行确认，只需通过以下链接

https://www.sanfoundry.com/java-program-check-given-number-perfect-number/