java - 如何控制用户输入的内容？

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How do I compare strings in Java? (23 个回答)

已关闭 6 年前。

我是一名 Java 初学者，我正在阅读 First head Java 书籍。我确实做到了书中要求的内容，但我正在努力改进该程序

程序应该生成一个 0-7 之间的随机数，然后将其放入一个包含以下两个数字的数组中，用户必须猜测它。一切正常，除了我试图限制用户输入除 0 到 7 之间的数字之外的任何内容

这是我的尝试，我不知道为什么它不起作用:

public String  checkYourSelf (String stringGuess){
    String result = "miss"; //this will be returned if the guess doesn't match
    if (stringGuess != "0" ||
        stringGuess != "1" ||
        stringGuess != "2" ||
        stringGuess != "3" ||
        stringGuess != "4" ||
        stringGuess != "5" ||
        stringGuess != "6" ||
        stringGuess != "7" ){
            System.out.println("Please Enter a correct number");
            result = "error";
            return result;
        } 

之后我使用 parseInt 方法

int guess = Integer.parseInt(stringGuess);

整个方法:

    public String  checkYourSelf (String stringGuess){
    String result = "miss"; // this will be returned if the guess doesn't match
    if (stringGuess != "0" ||
        stringGuess != "1" ||
        stringGuess != "2" ||
        stringGuess != "3" ||
        stringGuess != "4" ||
        stringGuess != "5" ||
        stringGuess != "6" ||
        stringGuess != "7" ){
            System.out.println("Please Enter a correct number");
            result = "error";
            return result;
        } 
    int guess = Integer.parseInt(stringGuess);

    for (int cell : cellsLocations) {
        if (enterdNums.contains(guess)){
            result = "error";
            System.out.println ("You've entered this number already.");
            System.out.println("Please try again");
            break;
        }
        if (cell == guess) {
            result = "hit";
            hits++;      
            break;
        }
    }
    if (hits == cellsLocations.length) {
        result = "kill"; 
    }
    if (result != "error"){ 
        System.out.println(result);
    }
    enterdNums.add(guess); // add to the list so it doesnt
    return result;   
}
    }

在主方法中:

while (isAlive) {
        guess = input.getUserInput("Enter a number");
        result = dot.checkYourSelf(guess);
        if (result == "error"){
            continue;
            } 
        numOfGuesses++;

        if (result == "kill"){
            System.out.println(numOfGuesses);
            isAlive = false;
            break;
        } 
    }

我知道可能还有其他方法可以做到这一点，但我正在尝试用我已经知道的东西来做到这一点，从逻辑上讲，这应该可行，但是如果我输入任何数字，它会说“请输入正确的数字” ”

谢谢

Answer 1

使用 while 循环。其简单且易于实现

guess = input.getUserInput("Enter a number");
while(guess < 0 || guess > 7){
    System.out.println("that number is invalid! Enter a number 0-7 : ");
    guess = input.getUserInput("Enter a number");
}

循环将迭代，直到用户输入 0-7 之间的数字