为什么每次迭代都会重置此代码中的'output'变量？ [英] Why does the 'output' variable in this code get reset every iteration?

问题描述

大家好，我正在阅读一本JS书，其中一个挑战让我们在1到100之间循环所有整数，如果它可以被3整除则写Fizz，如果它可以被5整除则写Buzz和FizzBu​​zz如果它可以被两者整除，否则只记录数字。我设法解决了问题的代码，但我不确定为什么每次迭代都会重置'output'声明，而不是存储一长串的Fizzes和Buzzes。这是代码：

Hi guys, I'm reading a JS book at the moment and one of the challenges had us loop over all integers between 1 - 100 and write "Fizz" if it's divisible by 3, "Buzz" if it's divisible by 5 and "FizzBuzz" if it's divisible by both, otherwise just log the number. I managed to work out the code for the problem but I'm unsure as to why the 'output' declaration gets reset every iteration rather than storing a long line of Fizzes and Buzzes. Here's the code:

for (let num = 1; num <= 100; num++){
	let output = "";
	if(num % 3 == 0) output += "Fizz";
	if(num % 5 == 0) output += "Buzz";
	console.log(output || num);
    }

我的尝试：



我试过谷歌搜索问题，但我找不到任何具体的变量为什么有时会重置每次迭代，而有时它会一遍又一遍地存储以连接所有内容。

What I have tried:

I've tried googling the question but I can't find anything specific as to why a variable sometimes resets each iteration, whereas sometimes it gets stored over and over to concatenate everything.

推荐答案

这是因为你在循环中声明它 。在循环外声明它以连接每次迭代：

It's because you declare it inside the loop. Declare it outside the loop to concatenate each iteration:

let output = "";
for (let num = 1; num <= 100; num++){
	if(num % 3 == 0) output += "Fizz";
	if(num % 5 == 0) output += "Buzz";
	console.log(output || num);
}

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