Structured programming says you should only ever have one return statement per function. This is to limit the complexity. Many people such as Martin Fowler argue that it is simpler to write functions with multiple return statements. He presents this argument in the classic refactoring book he wrote. This works well if you follow his other advice and write small functions. I agree with this point of view and only strict structured programming purists adhere to single return statements per function.

I lean towards using guard clauses to return early and otherwise exit at the end of a method. The single entry and exit rule has historical significance and was particularly helpful when dealing with legacy code that ran to 10 A4 pages for a single C++ method with multiple returns (and many defects). More recently, accepted good practice is to keep methods small which makes multiple exits less of an impedance to understanding. In the following Kronoz example copied from above, the question is what occurs in //Rest of code...?:

void string fooBar(string s, int? i) {

  if(string.IsNullOrEmpty(s) || i == null) return null;

  var res = someFunction(s, i);

  foreach(var r in res) {
      if(!r.Passed) return null;
  }

  // Rest of code...

  return ret;
}

我意识到这个例子有点做作，但我很想把foreach循环重构成一个LINQ语句，然后将其视为一个保护子句。同样，在一个人为的例子中，代码的意图并不明显，someFunction()可能会有一些其他副作用，或者结果可能会在代码的// Rest中使用....

if (string.IsNullOrEmpty(s) || i == null) return null;
if (someFunction(s, i).Any(r => !r.Passed)) return null;

给出以下重构函数:

void string fooBar(string s, int? i) {

  if (string.IsNullOrEmpty(s) || i == null) return null;
  if (someFunction(s, i).Any(r => !r.Passed)) return null;

  // Rest of code...

  return ret;
}

I've seen it in coding standards for C++ that were a hang-over from C, as if you don't have RAII or other automatic memory management then you have to clean up for each return, which either means cut-and-paste of the clean-up or a goto (logically the same as 'finally' in managed languages), both of which are considered bad form. If your practices are to use smart pointers and collections in C++ or another automatic memory system, then there isn't a strong reason for it, and it become all about readability, and more of a judgement call.

我通常的策略是在函数的末尾只有一个return语句，除非通过添加更多的return语句来大大降低代码的复杂性。事实上，我是Eiffel的粉丝，它通过没有return语句强制执行唯一的返回规则(只有一个自动创建的'result'变量来放入结果)。

当然，在某些情况下，有多个返回值的代码比没有返回值的代码更清晰。有人可能会说，如果一个函数太复杂，没有多个return语句就无法理解，那么就需要更多的返工，但有时对这种事情采取务实的态度是好的。

我想说的是，你应该有尽可能多的需要，或者任何使代码更干净的(如保护子句)。

我个人从来没有听过/见过任何“最佳实践”说你应该只有一个返回语句。

在大多数情况下，我倾向于根据逻辑路径尽快退出函数(保护子句就是一个很好的例子)。

函数中return语句越多，该方法的复杂性就越高。如果您发现自己想知道是否有太多的return语句，那么您可能需要问问自己，该函数中是否有太多的代码行。

但是，不是，一个/多个返回语句并没有错。在某些语言中，这是一种比其他语言(C)更好的实践(c++)。