Javascript 我的while循环接受它不应该接受的答案';T为什么?
我有一个while循环无法正常工作,无法找到问题。例如,我可以输入一个“L”,它不会启动循环。有人看到我的问题了吗Javascript 我的while循环接受它不应该接受的答案';T为什么?,javascript,loops,Javascript,Loops,我有一个while循环无法正常工作,无法找到问题。例如,我可以输入一个“L”,它不会启动循环。有人看到我的问题了吗 <script> var wood = prompt("Enter wood type (M)ahogany, (O)ak, (P)ine"); while (wood != "M" && wood != "m" && wood != "O" && wood != "o" && wood != "
<script>
var wood = prompt("Enter wood type (M)ahogany, (O)ak, (P)ine");
while (wood != "M" && wood != "m" && wood != "O" && wood != "o" && wood != "P" && wood != "p" && wood == "")
{
wood = prompt("invalid wood please enter (M)ahogany, (O)ak, (P)ine ");
}
</script>
var wood=提示(“输入木材类型(M)ahogany,(O)ak,(P)ine”);
而(wood!=“M”&&wood!=“M”&&wood!=“O”&&wood!=“O”&&wood!=“P”&&wood!=“P”&&wood=”)
{
wood=提示(“无效的wood请输入(M)ahogany,(O)ak,(P)ine”);
}
&&wood==”
。。。仅当wood
为空时才为true,因此在条件中传递的唯一值是空字符串
你可以把它改成
while ((wood != "M" && wood != "m" && wood != "O" && wood != "o" && wood != "P" && wood != "p") || (wood == "")) { ...
或者通过使用字符串来简化它。包括
var woods = "MOP";
var wood = prompt("Enter wood type (M)ahogany, (O)ak, (P)ine");
while (!( wood && woods.includes(wood.toUpperCase()) )) {
wood = prompt("invalid wood please enter (M)ahogany, (O)ak, (P)ine ");
}
如上所述,您需要将空字符串改为“OR”而不是“AND” 不过,我可能会写得更可读一些,比如
let woods = ['M','O','P'];
while (!wood || !woods.includes(wood.toUpperCase()))
这样,您就不需要将一系列不同的变体链接起来。只需将其放入数组中一次,并将输入中的任何内容都设置为大写
希望这有帮助