VAR＆QUOT;＆的使用QUOT;类型变量声明 [英] Use of "var" type in variable declaration

问题描述

我们的内部审计建议我们使用，而不是使用关键字明确的变量类型声明 VAR 。他们认为，使用变种可能导致在某些情况下意外的结果。

Our internal audit suggests us to use explicit variable type declaration instead of using the keyword var. They argue that using of var "may lead to unexpected results in some cases".

我不知道明确的类型声明，并使用变种之间的差异一旦code编译成MSIL。

I am not aware of any difference between explicit type declaration and using of var once the code is compiled to MSIL.

审核员是一个受人尊敬的职业，所以我不能简单地拒绝这样的建议。

The auditor is a respected professional so I cannot simply refuse such a suggestion.

推荐答案

这个怎么样？

double GetTheNumber()
{
    // get the important number from somewhere
}

和其他地方的话...

And then elsewhere...

var theNumber = GetTheNumber();
DoSomethingImportant(theNumber / 5);

然后，在未来的某个时刻，有人注意到 GetTheNumber 只会返回整数所以refactors它返回 INT ，而不是双击。

And then, at some point in the future, somebody notices that GetTheNumber only ever returns whole numbers so refactors it to return int rather than double.

砰！没有编译器错误和你开始看到意想不到的效果，因为什么是previously浮点运算现已成为整数运算，却没有人注意到。

Bang! No compiler errors and you start seeing unexpected results, because what was previously floating-point arithmetic has now become integer arithmetic without anybody noticing.

话虽如此，这样的事情的应的被你的单元测试等抓住了，但它仍然是一个潜在的疑难杂症。

Having said that, this sort of thing should be caught by your unit tests etc, but it's still a potential gotcha.

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