Javascript eval函数返回八进制值 [英] Javascript eval function returning Octal value

问题描述

当我尝试eval函数作为eval（020 * 05 + 05）时，它返回85而不是105.
有人可以解释为什么eval函数的行为如下吗？还建议任何解决这个问题。

when i try "eval" function as eval ("020 * 05 + 05") it is returning 85 instead off 105. Can someone explain me why eval function behave like this? Also suggest any to overcome this problem.

推荐答案

以零开头的数字常量（如020）被解释为八进制。这对于C，C ++，Java，Javascript以及大多数其他语言来说都是如此，甚至与C语言的模糊关系也很模糊。

Numeric constants that start with a zero (like "020") are interpreted as octal. That's true for C, C++, Java, Javascript, and most any other language with even a vague cosmetic relationship to C.

如果由于某种原因你确实需要使用eval（），你有这些奇怪的字符串，数字常量上带有伪造的前导零，你可能会尝试这样的事情：

If for some reason you really, really need to use "eval()", and you've got these weird strings with bogus leading zeros on the numeric constants, you might try something like this:

var answer = eval(weirdString.replace(/\b0(\d+)\b/g, '$1'));

但是我希望你能找到一种方法来使用eval（）。 （请注意下面的注释，注意上面显示的hack会出现包含小数部分的数字的问题。）

However I wish you would find a way around using "eval()" at all. (Note the comment below noting that the hack shown above will have problems with numbers containing fractional parts.)

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