Question

我正在尝试学习JavaScript，当我开始MDN教程时，我尝试单独进行第一个练习，到目前为止效果还不错。但是确实有一种奇怪的情况。

游戏会生成一个1到100之间的随机数，并且用户有10个猜测来找出该数字。

为此我将游戏简化为1-10。

当随机数是9而我猜是10时，代码显示我的输入值太低。我不明白为什么会这样。在任何其他情况下，它的工作都完全符合预期。

出于调试原因，第一次猜测后，对话框中会显示随机数。

这是我的代码：

var number = 0;
var turns = 0;
var guess = 0;
var won = false;

playGame();

function playGame() {
    won = false;
    number = (Math.random() * 10).toFixed(0);
    guess = prompt("Guess a number from 1 to 10");
    turns = 0;

    while(turns < 10) {
        console.log(number + " " + guess);
        if(guess < number) {
            turns++;
            guess = prompt("Number is " + number + ".\n\nYou guessed " + turns + " Times already.\n\nYour guess was to low! Guess again:");
            won = false;
        } else if(guess > number) {
            turns++;
            guess = prompt("Number is " + number + ".\n\nYou guessed " + turns + " Times already.\n\nYour guess was to high! Guess again:");
            won = false;
        } else if(guess === number) {
            alert("You got it!");
            won = true;
            break;
        }
    }
    if(confirm("Wanna play again?")){
        playGame()
    } else {
        alert("kkbye!");
    }   
}

先谢谢了。如果您想在代码中看到某些内容想要发表评论，我希望能收到反馈并变得更好，即使它与该内容没有直接关系;）

Answer 1

问题是，您正在使用字符串，如果将两个字符串与<进行比较，它将只比较所需的字符，直到找到较小的字符为止（较小的是整数表示））比另一个：

console.log("10" < "9");

此处只会将"1"与"9"进行比较，这意味着将字符代码49与字符代码57相比较。

49小于57，表示整个表达式为true。您可以了解有关ASCII字符代码here的更多信息。

您应该改用Numbers：

console.log(Number("10") < Number("9"));

您仅在处理字符串，因为prompt()和Number.toFixed()都返回字符串。如果将这些内容封装在Number()调用中，则您的游戏有效：

var number = 0;
var turns = 0;
var guess = 0;
var won = false;

playGame();

function playGame() {
    won = false;
    number = Number((Math.random() * 10).toFixed(0));
    guess = Number(prompt("Guess a number from 1 to 10"));
    turns = 0;

    while(turns < 10) {
        console.log(number + " " + guess);
        if(guess < number) {
            turns++;
            guess = prompt("Number is " + number + ".\n\nYou guessed " + turns + " Times already.\n\nYour guess was too low! Guess again:");
            won = false;
        } else if(guess > number) {
            turns++;
            guess = prompt("Number is " + number + ".\n\nYou guessed " + turns + " Times already.\n\nYour guess was too high! Guess again:");
            won = false;
        } else if(guess === number) {
            alert("You got it!");
            won = true;
            break;
        }
    }
    if(confirm("Wanna play again?")){
        playGame()
    } else {
        alert("kkbye!");
    }   
}

Answer 2

Javascript提示返回一个字符串。实际上，输入文本框始终返回字符串。因此，当您输入10时，它将返回“ 10”，并且toFixed（）也将返回字符串。

因此您需要从代码中更正两行

number = parseInt((Math.random() * 10).toFixed(0));
guess = prompt("Guess a number from 1 to 10");
guess = parseInt(guess);

此外，您还需要检查NAN状况是否更安全。

JavaScript说10比9低

2 个答案: