无法检测到为什么我的循环是无限的

Question

 var randomNum = Math.round(Math.random() * 100); guesses = prompt("guess a number between 1 and 100"); var scores = 0; while (randomNum < 100) { if (guesses < randomNum) { console.log(" too low.. continue") } else if (guesses > randomNum) { console.log("too high ... continue "); score++; } else if (guesses === randomNum) { console.log("great ... that is correct!!") } else { console.log("game over ... your guess was right " + scores + " times"); } } 

I have been struggling with the while loop concept for some time now and in order to confront my fears I decided to practice with some tiny exercises like the one above.

Answer 1

您不会增加randomNum，因此它将始终处于无限循环中。

Answer 2

You initialize randonNum and guesses at the beginning of your code, but then you never change their values again. So, once you go inside the while loop and the condition starts out to be false, then there is nothing inside the while loop to ever change the outcome of the comparison condition. Thus, the condition is always false and you end up with an infinite loop. Your loop structure boils down to this:

while (randomNum < 100) {
    // randomNum never changes
    // there is no code to ever break or return out of the loop
    // so loop is infinite and goes on forever
}

You can fix the problem by either putting a condition in the loop that will break out of the loop with a break or return or you can modify the value of randomNum in the loop such that eventually the loop will terminate on its own.

In addition, guesses === randomNum will never be true because guesses is a string and randomNum is a number so you have to fix that comparison too.

---

It's not 100% clear what you want to achieve, but if you're trying to have the user repeatedly guess the number until they get it right, then you need to put a prompt() inside the while loop and a break out of the while loop when they get it right or ask to cancel:

var randomNum = Math.round(Math.random() * 100);
var guess;
var score = 0;
while ((guess = prompt("guess a number between 1 and 100")) !== null) {
    // convert typed string into a number
    guess = +guess;
    if (guess < randomNum) {
        console.log(" too low.. continue")
    } else if (guess > randomNum) {
        console.log("too high ... continue ");
        score++;
    } else if (guess === randomNum) {
        console.log("great ... that is correct!!")
        console.log("score was: " + score);
        // when we match, stop the while loop
        break;
    }
}

Answer 3

the below line of code of your assign randomNum only one time hence it doesn't change

var randomNum = Math.round(Math.random() * 100);

so when you are trying to create the while loop the randomNum value remains same

try changing the randomNum value in the while loop

Answer 4

I think this is what you tried to achieve. Retry x number of times

 var randomNum = Math.round(Math.random() * 100); var guesses; var scores = 0; var tries = 0 while (tries++ < 3) { // Loop if less than 3 tries, and increment guesses = prompt("guess a number between 1 and 100"); if (guesses < randomNum) { console.log(" too low.. continue") } else if (guesses > randomNum) { console.log("too high ... continue "); } else { // It's not to low, not to high. It must be correct score++; console.log("great ... that is correct!!"); randomNum = Math.round(Math.random() * 100); } } console.log("game over ... your guess was right " + scores + " times");