通过const引用传递，除非有原因你希望改变/保留你传递的内容。

在大多数情况下，这将是最有效的方法。

确保对不想更改的每个形参都使用const，因为这不仅可以防止您在函数中做一些愚蠢的事情，还可以很好地向其他用户指示函数对传入的值做了什么。这包括当你只想改变所指向的对象时，创建一个const指针…

我的经验法则是:

如果你想对指针进行算术运算(例如，增加指针地址以遍历数组)，或者如果你必须传递一个空指针，请使用指针。

否则使用引用。

这最终是主观的。到目前为止的讨论是有用的，但我不认为有一个正确或决定性的答案。这在很大程度上取决于风格指南和您当时的需求。

While there are some different capabilities (whether or not something can be NULL) with a pointer, the largest practical difference for an output parameter is purely syntax. Google's C++ Style Guide (https://google.github.io/styleguide/cppguide.html#Reference_Arguments), for example, mandates only pointers for output parameters, and allows only references that are const. The reasoning is one of readability: something with value syntax should not have pointer semantic meaning. I'm not suggesting that this is necessarily right or wrong, but I think the point here is that it's a matter of style, not of correctness.

引用类似于指针，除了不需要使用前缀*来访问引用所引用的值。同样，在初始化对象之后，不能引用另一个对象。

引用对于指定函数参数特别有用。

有关更多信息，请参阅“Bjarne Stroustrup”(2014)的“c++之旅”(A Tour of c++)第11-12页

我真的认为你将受益于建立以下函数调用编码指南:

As in all other places, always be const-correct. Note: This means, among other things, that only out-values (see item 3) and values passed by value (see item 4) can lack the const specifier. Only pass a value by pointer if the value 0/NULL is a valid input in the current context. Rationale 1: As a caller, you see that whatever you pass in must be in a usable state. Rationale 2: As called, you know that whatever comes in is in a usable state. Hence, no NULL-check or error handling needs to be done for that value. Rationale 3: Rationales 1 and 2 will be compiler enforced. Always catch errors at compile time if you can. If a function argument is an out-value, then pass it by reference. Rationale: We don't want to break item 2... Choose "pass by value" over "pass by const reference" only if the value is a POD (Plain old Datastructure) or small enough (memory-wise) or in other ways cheap enough (time-wise) to copy. Rationale: Avoid unnecessary copies. Note: small enough and cheap enough are not absolute measurables.

可以时使用引用，必要时使用指针。 来自c++常见问题:“什么时候应该使用引用，什么时候应该使用指针?”