blocks|key|2451919|text|来简化物质。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2451920|在这些语言中，您总是可以返回T[]、Pair<L,R>、Set<E>等，以模拟返回多个值。这可以处理大多数多个return值的场景。|offset|length|style|CODE|2451921|为了这么少的收获而改变语言的语义是不值得的。|2451922|相关问题|2451923|2451924|+Using+a+java+method+to+return+multiple+values?+|unordered-list-item|2451925|+Returning+multiple+values+from+a+C%2B%2B+function+|2451926|+Returning+multiple+values+from+a+C+function+|2451927|+Method+should+return+multiple+values+|2451928|+Elegant+ways+to+return+multiple+values+from+a+function+|2451929|2451930|entityMap|0|LINK|mutability|MUTABLE|url|https://stackoverflow.com/questions/1736061/using-a-java-method-to-return-multiple-values|1|https://stackoverflow.com/questions/321068/returning-multiple-values-from-a-c-function|2|https://stackoverflow.com/questions/1088646/returning-multiple-values-from-a-c-function|3|https://stackoverflow.com/questions/2918861/method-should-return-multiple-values|4|https://stackoverflow.com/questions/514038/elegant-ways-to-return-multiple-values-from-a-function^0|0|E|3|I|9|S|6|1J|6|0|0|0|0|0|1C|0|0|0|1B|1|0|0|19|2|0|0|12|3|0|0|1K|4|0|0^^$0|@$1|2|3|4|5|6|7|1E|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|1F|8|@$D|1G|E|1H|F|G]|$D|1I|E|1J|F|G]|$D|1K|E|1L|F|G]|$D|1M|E|1N|F|G]]|9|@]|A|$]]|$1|H|3|I|5|6|7|1O|8|@]|9|@]|A|$]]|$1|J|3|K|5|6|7|1P|8|@]|9|@]|A|$]]|$1|L|3|-4|5|6|7|1Q|8|@]|9|@]|A|$]]|$1|M|3|N|5|O|7|1R|8|@]|9|@$D|1S|E|1T|1|1U]]|A|$]]|$1|P|3|Q|5|O|7|1V|8|@]|9|@$D|1W|E|1X|1|1Y]]|A|$]]|$1|R|3|S|5|O|7|1Z|8|@]|9|@$D|20|E|21|1|22]]|A|$]]|$1|T|3|U|5|O|7|23|8|@]|9|@$D|24|E|25|1|26]]|A|$]]|$1|V|3|W|5|O|7|27|8|@]|9|@$D|28|E|29|1|2A]]|A|$]]|$1|X|3|-4|5|6|7|2B|8|@]|9|@]|A|$]]|$1|Y|3|-4|5|6|7|2C|8|@]|9|@]|A|$]]]|Z|$10|$5|11|12|13|A|$14|15]]|16|$5|11|12|13|A|$14|17]]|18|$5|11|12|13|A|$14|19]]|1A|$5|11|12|13|A|$14|1B]]|1C|$5|11|12|13|A|$14|1D]]]]

To simplify matter.

You can always return a <code>T[]</code>, <code>Pair&lt;L,R&gt;</code>, <code>Set&lt;E&gt;</code>, etc in these languages to emulate returning multiple values. That takes care of most multiple <code>return</code> values scenarios out there.

It's not worth changing the semantics of the language so much for a gain so little.

<h3>Related questions</h3>

<ul>
<li><a href="https://stackoverflow.com/questions/1736061/using-a-java-method-to-return-multiple-values"> Using a java method to return multiple values? </a></li>
<li><a href="https://stackoverflow.com/questions/321068/returning-multiple-values-from-a-c-function"> Returning multiple values from a C++ function </a></li>
<li><a href="https://stackoverflow.com/questions/1088646/returning-multiple-values-from-a-c-function"> Returning multiple values from a C function </a></li>
<li><a href="https://stackoverflow.com/questions/2918861/method-should-return-multiple-values"> Method should return multiple values </a></li>
<li><a href="https://stackoverflow.com/questions/514038/elegant-ways-to-return-multiple-values-from-a-function"> Elegant ways to return multiple values from a function </a></li>
</ul>

blocks|key|742361|text|一个函数(使用您在标记中提到的语言)确实有一个输出，但该输出不一定是单个value。您的输出可以很容易地成为一个类，它封装了您想要的任意数量的数据。|type|unstyled|depth|inlineStyleRanges|offset|length|style|BOLD|entityRanges|data|742362|此外，请注意，您还可以通过引用将多个输入参数传递给函数，从而增加返回的输出数量。|742363|entityMap^0|N|2|10|5|0|M|I|0^^$0|@$1|2|3|4|5|6|7|J|8|@$9|K|A|L|B|C]|$9|M|A|N|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|O|8|@$9|P|A|Q|B|C]]|D|@]|E|$]]|$1|H|3|-4|5|6|7|R|8|@]|D|@]|E|$]]]|I|$]]

A function (in languages you mentioned in your tags) does have a single output , but that output does not have to be a single value. Your output can easily be a class which encapsulates any amount of data you want.

Also, note that you can also pass multiple input arguments by reference to your function, thereby increasing the number of returned outputs.

blocks|key|2452021|text|这个函数返回一个答案，为什么它会被设计成提供更多的答案呢？答案可以是您喜欢的任何数据结构，因此它可以包含很多值:)|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2452022|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

The function return an answer, why would it be designed to give more answers? And that answer can be any data structure you like so it could hold lots of values :)

blocks|key|3860132|text|谷歌的Go支持多个return+values|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|3860133|entityMap|0|LINK|mutability|MUTABLE|url|http://golang.org/|1|http://golang.org/doc/go_spec.html#Return_statements^0|3|2|0|9|D|1|0^^$0|@$1|2|3|4|5|6|7|N|8|@]|9|@$A|O|B|P|1|Q]|$A|R|B|S|1|T]]|C|$]]|$1|D|3|-4|5|6|7|U|8|@]|9|@]|C|$]]]|E|$F|$5|G|H|I|C|$J|K]]|L|$5|G|H|I|C|$J|M]]]]

Google's <a href="http://golang.org/" rel="nofollow noreferrer">Go</a> supports multiple <a href="http://golang.org/doc/go_spec.html#Return_statements" rel="nofollow noreferrer">return values</a>

blocks|key|1487728|text|我最好的猜测是它是从数学中继承下来的。在那里，你可以有一个具有多个参数的函数，而value就是结果。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1487729|f(x1,+x2,+...)+=+y+(the+formula+might+be+something+like+x1+%2B+x2%5E2+%2B+x3%5E3+%2B+...)|code-block|syntax|javascript|1487730|即使你想把一个多维域映射到一个多维范围，你通常会写成：|1487731|f1(x1,+x2,+...)+=+y1+(perhaps+y1+=+x1+%2B+x2%5E1+%2B+...+like+above)
f2(x1,+x2,+...)+=+y2+(and+y2+=+x1+-+x2%5E2+%2B+x3%5E3+-+x4%5E4+%2B...)
...|1487732|由于每个y都会根据输入得到自己的数学公式，在编程中，这些公式只是转换为多个函数，所以像这样将其分开是有意义的。|1487733|问题是，有时y1和y2的公式可能非常相似，或者依赖于迭代相同的东西或诸如此类的东西，将它们放在一起可能更有意义。在python中，您可以执行以下操作|1487734|返回a1，a2；|1487735|然后叫它像这样|1487736|x，y=+f()；|1487737|但在大多数语言中，您只能返回一个变量。但这并不能阻止您使其成为包含多个值的复杂对象。|1487738|entityMap^0|0|0|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Y|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|Z|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|10|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|11|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|12|8|@]|9|@]|A|$]]|$1|M|3|N|5|6|7|13|8|@]|9|@]|A|$]]|$1|O|3|P|5|6|7|14|8|@]|9|@]|A|$]]|$1|Q|3|R|5|6|7|15|8|@]|9|@]|A|$]]|$1|S|3|T|5|6|7|16|8|@]|9|@]|A|$]]|$1|U|3|V|5|6|7|17|8|@]|9|@]|A|$]]|$1|W|3|-4|5|6|7|18|8|@]|9|@]|A|$]]]|X|$]]

My best guess is that it carried over from mathematics. There you can have a function with multiple parameters, and value that's the result.

<pre><code>f(x1, x2, ...) = y (the formula might be something like x1 + x2^2 + x3^3 + ...)
</code></pre>

Even if you want to map a multidimensional domain to a multidimensional range you usually write as:

<pre><code>f1(x1, x2, ...) = y1 (perhaps y1 = x1 + x2^1 + ... like above)
f2(x1, x2, ...) = y2 (and y2 = x1 - x2^2 + x3^3 - x4^4 +...)
...
</code></pre>

since each y gets it's own mathematical formula based on the inputs, which in programming would just translate to multiple functions, it makes sense to separate it like this.

The problem is sometimes the formulas for y1 and y2 may be very similar or rely on iterating the same thing or whatnot, that doing them together might make more sense. In python you can do

return a1, a2;

and then call it like

x, y = f();

but in most languages you can only return one variable. That doesn't stop you from making it a complex object with multiple values included.

blocks|key|1487744|text|您可以在perl中做到这一点：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1487745|sub+foo
{
+++return+(10,+20);
}

my+($a,+$b)+=+foo();++#+sets+$a+to+10+and+$b+to+20|code-block|syntax|javascript|1487746|以及其他语言中的类似构造。|1487747|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

You can do this in perl:

<pre><code>sub foo
{
 return (10, 20);
}

my ($a, $b) = foo(); # sets $a to 10 and $b to 20
</code></pre>

And similar constructs in other languages.

blocks|key|3860209|text|函数只返回一个值，因为这是“他们”在以前的汇编程序中发明的方法。基本上发生的是函数将返回值推送到堆栈上。然后调用者从堆栈中弹出值。如果函数返回更多的值，调用者将不知道要弹出多少值，堆栈将不平衡(导致程序崩溃)。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3860210|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

Functions return only one value because its the way "they" invented it in the old days of assembler. Basically what happens is that function pushes return value on the stack. Caller then pops the value from the stack. If function returned more values, caller wouldnt know how many values to pop and the stack would be unbalanced (leading to program crash).

blocks|key|742527|text|我猜在大多数情况下一个返回值就足够了，一个函数(或Lambda演算)的数学概念也有一个返回值，所以语言设计者试图坚持“标准”是可以理解的。事实上，拥有几个需要多个返回值的函数可能会令人困惑，并且可能是设计不佳的标志，例如缺少一个复合类。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|742528|返回多个值的“经典”方法是使用元组。一些语言有一个内置的Tuple类型(如Scala)，但您可以在支持某种形式的类型参数的所有语言中自己定义它(模板、泛型...)。对于Java，有一个很好的JavaTuple库。|offset|length|742529|entityMap|0|LINK|mutability|MUTABLE|url|http://javatuple.com/^0|0|2N|9|0|0^^$0|@$1|2|3|4|5|6|7|N|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|O|8|@]|9|@$D|P|E|Q|1|R]]|A|$]]|$1|F|3|-4|5|6|7|S|8|@]|9|@]|A|$]]]|G|$H|$5|I|J|K|A|$L|M]]]]

I guess in most cases one return value is sufficient, and the mathematical notion of a function (or Lambda calculus) has one return value as well, so it's kind of understandable that language designers try to stick with the "standard". In fact having several functions which need multiple return values can be confusing and may be a sign of poor design, e.g. a missing compound class.

The "classical" approach for returning multiple values is using Tuples. Some languages have a built-in Tuple type (like Scala), but you can define it yourself in all languages that support type parameters in some form (templates, generics...). For Java, there is the nice <a href="http://javatuple.com" rel="nofollow noreferrer">JavaTuple</a> lib.

blocks|key|744848|text|它是为了帮助阅读源代码。这样对人类来说太友好了！如果此函数有多个返回值，则无法编写以下代码行：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|744849|+if+(SomeFunction(a,+b)+!=+SUCCESS)
+{
++++//+do+error+handling
+}|code-block|syntax|javascript|744850|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

It is to help reading source code.
It's SOOOOO human-friendly this way!
If this function would have more than one return value, this line could not be written:

<pre><code> if (SomeFunction(a, b) != SUCCESS)
 {
 // do error handling
 }
</code></pre>

blocks|key|3860330|text|一个函数必须完成一个明确定义的任务。除了你总是可以返回一个数组的事实:如果你需要从不同的数据类型返回不同的值，那么你的软件设计可能是完全错误的。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3860331|除此之外，对于人类来说，读取只有一个返回值的函数要容易得多。|3860332|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|F|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|G|8|@]|9|@]|A|$]]|$1|D|3|-4|5|6|7|H|8|@]|9|@]|A|$]]]|E|$]]

A function has to fullfill a clearly defined task. Aside from the fact that you can always return an array: probably something was completely wrong with your softwaredesign if you'd need to return different values from different datatypes.

Besides that, it's much easier for a human to read a function with one return value.

blocks|key|3860358|text|Lua还支持多个返回值:例如，您可以编写以下代码：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3860359|function+foo()
++++return+1,+2,+3
end

a,+b,+c,+d+=+foo()|code-block|syntax|javascript|3860360|执行后，a，b，c将保持值1，2，3，d将为零。您可以通过相同的方式执行以下操作：|3860361|function+bar()
+++return+true,+2,+3
end

if+bar()+then
+++--+do+something+intelligent
end|3860362|在这种情况下，if语句只对返回的第一个值起作用-如果需要其他值，则必须像往常一样将它们存储在变量中：|3860363|a,+b,+c+=+bar()
if+a+then
+++--+do+something+intelligent
end|3860364|所以你可以看到:在Lua中，所有不需要的返回值都被丢弃了(就像示例中的2，3和if一样)。|3860365|entityMap^0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|T|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|U|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|V|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|W|8|@]|9|@]|A|$]]|$1|M|3|N|5|D|7|X|8|@]|9|@]|A|$E|F]]|$1|O|3|P|5|6|7|Y|8|@]|9|@]|A|$]]|$1|Q|3|-4|5|6|7|Z|8|@]|9|@]|A|$]]]|R|$]]

Lua does also support multiple return values: you can for example write the following:

<pre><code>function foo()
 return 1, 2, 3
end

a, b, c, d = foo()
</code></pre>

after execution, a, b, c will hold the values 1, 2, 3 and d will be nil. You can in the same way do the following:

<pre><code>function bar()
 return true, 2, 3
end

if bar() then
 -- do something intelligent
end
</code></pre>

the if statement will in this case only work with the first value returned - if you need the other values, you will have to store them in variables like usual:

<pre><code>a, b, c = bar()
if a then
 -- do something intelligent
end
</code></pre>

so you see: in Lua, all the return values that are not needed are thrown away (like 2, 3 in the example with the if).

blocks|key|3860417|text|Daniel+Weinreb+--他研究过Lisp方言(有多个返回值)和Java+(没有)，explains+why|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|3860418|3860419|当我们将多值返回特性添加到Lisp机器Lisp+(从那里进入Common+Lisp)时，我相信避免协商的愿望是一个重要的动机。当时，我们还没有很好的GC技术，并且编写Lisp程序来小心地最小化consing是非常普遍的。|blockquote|3860420|3860421|另一个原因是表现力:为了清楚地表明函数实际上返回了多个结果，而不是引入一个小小的列表“类型”(例如，“文件句柄的两个列表和一个布尔值来表示是否...”)。|3860422|在Java中，我见过一些小类的定义，它们的唯一目的是提供一种返回多个值的方法。这种方法的优点是记录了返回值的类型和含义(至少如果您选择清晰的名称并添加注释！)。但在我看来，这是相当冗长的。|3860423|当我第一次回顾早期的Java规范时，我惊讶地发现没有办法返回多个值。我想游说加入这一点，所以我试着想出一个既简单又非常引人注目的用例。我不能这样做！所以我没有试着去游说。很明显，Java的设计者试图避免许多花哨的东西(和语法糖)，这方面肯定有很多可说的。|3860424|entityMap|0|LINK|mutability|MUTABLE|url|http://lambda-the-ultimate.org/node/2833#comment-42536^0|1A|C|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|W|8|@]|9|@$A|X|B|Y|1|Z]]|C|$]]|$1|D|3|-4|5|6|7|10|8|@]|9|@]|C|$]]|$1|E|3|F|5|G|7|11|8|@]|9|@]|C|$]]|$1|H|3|-4|5|6|7|12|8|@]|9|@]|C|$]]|$1|I|3|J|5|6|7|13|8|@]|9|@]|C|$]]|$1|K|3|L|5|6|7|14|8|@]|9|@]|C|$]]|$1|M|3|N|5|6|7|15|8|@]|9|@]|C|$]]|$1|O|3|-4|5|6|7|16|8|@]|9|@]|C|$]]]|P|$Q|$5|R|S|T|C|$U|V]]]]

Daniel Weinreb -- who worked on both Lisp dialects (which had multiple return values) and Java (which didn't), <a href="http://lambda-the-ultimate.org/node/2833#comment-42536" rel="nofollow noreferrer">explains why</a>:

<blockquote>
 When we added the multiple-value return feature to Lisp machine Lisp (from whence it went into Common Lisp), I believe that the desire to avoid consing was one of the serious motivations. Back then, we did not have good GC technology, and writing Lisp programs to carefully minimize consing was very common.
 
 The other reason was for expressiveness: to make it clear that the function was really returning more than one result, rather than introducing a little list "type" (e.g. "a two-list of the file handle and a boolean to say whether...").
 
 In Java, I've seen definitions of little classes whose only purpose is to be a way to return multiple values. The advantage of this approach is that the types and meanings of the returned values are documented (at least if you pick clear names and put in comments!). But it's rather verbose, in my opinion.
 
 When I was first reviewing the early Java spec, I was surprised to see that there was no way to return multiple values. I wanted to lobby for adding that, so I tried to come up with a use case that was both simple and very compelling. I was unable to do so! So I didn't try lobbying for it. The designers of Java were pretty clearly trying to avoid a lot of bells and whistles (and syntactic sugar), and there's certainly a lot to be said for that.
</blockquote>

blocks|key|1490893|text|我认为问题是关于内存分配和堆栈组织，主要是在函数调用时的上下文切换。函数帧存储在堆栈中。函数帧包含函数变量、通用寄存器和返回值。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1490894|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

I think the question is about memory allocation and stack organization
The main thing is context switching at time of function call .
the function frame is stored on the stack
the frame contains function variables,general purpose registers and return values
i know that much

Why do functions in some popular languages return only a single type of result?

i.e I mean Why The Compilers give Error on Following Syntax 

<pre><code>public int int returnTwoIntegers(){
.......
........
}
</code></pre>

Why do functions in some popular languages return only a single type of result?

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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为什么一些流行语言中的函数只返回一种类型的结果？也就是说，我的意思是为什么编译器在遵循以下语法时会出现错误public int int  returnTwoIntegers(){...............}

问为什么一些流行语言中的函数只返回一种类型的结果？
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问为什么一些流行语言中的函数只返回一种类型的结果？EN