没有人提到或引用代码完成，所以我就这么做。

17.1返回

尽量减少每个例程的返回次数。如果在底部阅读一个例程，你没有意识到它可能会返回到上面的某个地方，那么理解它就更难了。

在增强可读性时使用返回。在某些例程中，一旦知道了答案，就希望立即将其返回给调用例程。如果例程以不需要任何清理的方式定义，则不立即返回意味着必须编写更多代码。

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.

作为嵌套if的替代方法，有一种使用do/while(false)在任何地方爆发的方法:

    function()
    {
        HRESULT error = S_OK;

        do
        {
            if(!SUCCEEDED(Operation1()))
            {
                error = OPERATION1FAILED;
                break;
            }

            if(!SUCCEEDED(Operation2()))
            {
                error = OPERATION2FAILED;
                break;
            }

            if(!SUCCEEDED(Operation3()))
            {
                error = OPERATION3FAILED;
                break;
            }
            if(!SUCCEEDED(Operation4()))
            {
                error = OPERATION4FAILED;
                break;
            }
        } while (false);

        return error;
    }

这为您提供了一个出口点，允许您进行其他嵌套操作，但仍然不是真正的深层结构。如果你不喜欢成功，你可以做任何失败的事情。这类事情还允许您在任意两个其他检查之间添加其他代码，而无需重新缩进任何内容。

如果你真的疯了，整个If块也可以宏化。: D

    #define BREAKIFFAILED(x,y) if (!SUCCEEDED((x))) { error = (Y); break; }

    do
    {
        BREAKIFFAILED(Operation1(), OPERATION1FAILED)
        BREAKIFFAILED(Operation2(), OPERATION2FAILED)
        BREAKIFFAILED(Operation3(), OPERATION3FAILED)
        BREAKIFFAILED(Operation4(), OPERATION4FAILED)
    } while (false);

I always avoid multiple return statements. Even in small functions. Small functions can become larger, and tracking the multiple return paths makes it harder (to my small mind) to keep track of what is going on. A single return also makes debugging easier. I've seen people post that the only alternative to multiple return statements is a messy arrow of nested IF statements 10 levels deep. While I certain agree that such coding does occur, it isn't the only option. I wouldn't make the choice between a multiple return statements and a nest of IFs, I'd refactor it so you'd eliminate both. And that is how I code. The following code eliminates both issues and, in my mind, is very easy to read:

public string GetResult()
{
    string rv = null;
    bool okay = false;

    okay = PerformTest(1);

    if (okay)
    {
        okay = PerformTest(2);
    }

    if (okay)
    {
        okay = PerformTest(3);
    }

    if (okay)
    {
        okay = PerformTest(4);
    };

    if (okay)
    {
        okay = PerformTest(5);
    }

    if (okay)
    {
        rv = "All Tests Passed";
    }

    return rv;
}

我能想到的一个很好的理由是代码维护:您有一个单一的退出点。如果你想改变结果的格式，…，它的实现要简单得多。此外，为了调试，你可以在那里插入一个断点:)

话虽如此，我曾经不得不在一个库中工作，那里的编码标准强制要求“每个函数一个返回语句”，我发现这相当困难。我写了很多数值计算代码，经常有“特殊情况”，所以代码最终很难跟上……

我通常支持多个return语句。它们是最容易阅读的。

在某些情况下，这并不好。有时从函数返回可能非常复杂。我记得有一种情况，所有函数都必须链接到多个不同的库。一个库期望返回值是错误/状态代码，而其他库则不期望。使用一个return语句可以节省时间。

我很惊讶没人提到goto。Goto并不是每个人都想让你相信的编程的祸害。如果必须在每个函数中只有一个return语句，请将它放在末尾，并根据需要使用gotos跳转到该return语句。绝对避免标记和箭头编程，它们既丑陋又运行缓慢。