“If”語句不會循環打印

Question

我的代碼有效，只有一個問題。 該代碼旨在打印兩個用戶輸入之間的數字。 代碼的那部分有效，但是如果第一個數字大於第二個數字，則意味着不再打印並再次詢問。 到目前為止一切正常，但是如果第一個數字大於第二個，控制台和代碼就結束了，我不知道為什么？ 你們能幫忙解釋一下我做錯了什么嗎？ 謝謝！ 這是我的代碼：

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

您的循環僅在 highNum >=lowerNum 時開始，這意味着循環內的 if 條件永遠不會為真。

要實現您的輸出，您應該執行以下操作。

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

我建議您先使用 if 條件：

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++);
    }
}

發生這種情況是因為如果lowerNum大於higherNum您的while 條件將導致false 並且不會打印任何內容，因為錯誤消息在while 循環內。

Answer 3

你的 if 應該在 while 之前。 我在路上修了一些其他的東西。

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

您可以使用重新啟動過程的方法提供數字輸入。 遞歸選項將有助於解決該問題。

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++);

}

公共靜態無效主（字符串 [] args）{

TakeNumbers();

}

Answer 5

是的，它會在 for 循環內打印以進行確認，只需通過以下鏈接

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