我现任教同事.Net和他问了我一个问题，难倒我。

I am currently teaching a colleague .Net and he asked me a question that stumped me.

我们为什么要申报吗？

如果VAR是隐式类型，为什么我们连申报吗？

if var is implicit typing, why do we have to even declare?

Animal animal = new Animal();

变为

var animal = new Animal();

可能成为

animal = new Animal();

的隐式类型仍然意味着这是一个静态类型变量。

The implicit typing would still mean that this is a statically typed variable.

如果两个不同的类型分配给该变量，如果它们不共享一个基础类，（除其它对象），这可能是一个编译错误。

If two different types are assigned to the variable, if they do not share a base class, (other than object), that could be a compiler error.

是否有技术原因，这件事情不能做或者是风格上我们喜欢havein

Is there a technical reason this could not be done or is it stylistically we like havein

推荐答案

当然，这的将会的可能。

我能想到的一些原因，你不希望这样的：

I can think of a few reasons you don't want this:

什么是你的变量的范围？尚不清楚，如果你不告诉编译器。请问动物的两种方法成为私有变量或两个方法范围的变量？ 如果名称是什么一个错字？你永远不会知道。 如果你已经分配一个值，这个变量，然后尝试分配一个新的值，它是与上次不兼容（即JavaScript的方式）（学分的马里奥·斯托伊洛夫） What is the scope of your variable? Not clear if you don't tell the compiler. Will animals in two methods become a private variable or two method scoped variables? What if the name is a typo? You will never know. What if you already assigned a value to this variable and then try to assign a new value which is incompatible with the last (i.e javascript style) (credits to Mario Stoilov)