Question

下面的代码是我到目前为止所写的，所以没有实现。但是在程序中它会询问用户是否丢弃了最低等级。如果用户回答说“是”，“是”，“否”或“否”，则应该结束do循环并继续执行其余代码。

然而，即使我输入了正确的响应，它也会继续循环。我是一个非常新的java，所以如果这真的很愚蠢，请道歉。

代码：

import java.util.Scanner;
public class AvgGrade {

public static void main(String[] args) {
    // TODO Auto-generated method stub
    Scanner input = new Scanner(System.in);
    int numTest=1;


    //Test Number Checker
    while(numTest<=1) {
        System.out.println("How many tests were given out");
        System.out.println("Must be more than 1");
        numTest=input.nextInt();
    }

    //Lowest Grade Dropped Checker
    boolean droppedLow=false;
    String dropAnswer="default";
    do{
        System.out.println("Is the lowest grade dropped?");
        System.out.println("Answer: Yes, yes, No, no");
        dropAnswer=input.next();
    }
    while(dropAnswer.compareTo("Yes")!=0||dropAnswer.compareTo("yes")!=0||
              dropAnswer.compareTo("No")!=0||dropAnswer.compareTo("no")!=0);

    if(dropAnswer.equals("Yes")||dropAnswer.equals("yes"))
        droppedLow=true;
    else if(dropAnswer.equals("No")||dropAnswer.equals("no"))
        droppedLow=false;




    System.out.println("----------------DEBUG----------------");
    System.out.println(numTest);
    System.out.println(dropAnswer);
    System.out.println(droppedLow);
}

}

控制台/输出：

How many tests were given out
Must be more than 1
5
Is the lowest grade dropped?
Answer: Yes, yes, No, no
Yes
Is the lowest grade dropped?
Answer: Yes, yes, No, no
yes
Is the lowest grade dropped?
Answer: Yes, yes, No, no
no
Is the lowest grade dropped?
Answer: Yes, yes, No, no
No
Is the lowest grade dropped?
Answer: Yes, yes, No, no

Answer 1

无论你键入什么，这都将是真的，所以循环将永远持续：

dropAnswer.compareTo("Yes")!=0||dropAnswer.compareTo("yes")!=0||
    dropAnswer.compareTo("No")!=0||dropAnswer.compareTo("no")!=0

基本上，你的情况意味着“循环如果dropAnswer不等于'是'或它不等于'是'或它不等于'否'或者它不等于'不'。“至少有三个条件总是如此，因为没有字符串是'是'，'是'，'否'和'不'同时。

我认为您打算使用&&（和）代替||（或）：

dropAnswer.compareTo("Yes") != 0 && dropAnswer.compareTo("yes") != 0 &&
    dropAnswer.compareTo("No") != 0 && dropAnswer.compareTo("no") != 0

在字符串输入匹配条件后，while循环不断重复

1 个答案: