C＃不会让我来总结2短裤短 [英] C# does not let me sum two shorts to a short

问题描述

我有一个code：

 静态短总和（短，短B）
        {
            返回A + B;
        }
 

和它不编译，saynig不能转换'诠释'到'短'。我也许真的很累，但今天我看不到的问题！

解决方案

  

和它不编译，saynig不能转换'诠释'到'短'。我也许真的很累，但今天我看不到的问题！

这只是语言的定义方式。整数类型+操作为定义的：

 静态UINT OP +（UINT X，UINT Y）
静态INT运算+（INT X，int y）对
静态ULONG OP +（ULONG X，ULONG Y）
静态长运+（长×长Y）
 

按要求操作数被提升。

现在作为的的原因的为什么它的定义方式 - 我不知道，说实话。我不买的，因为它可能溢出的说法 - 这将表明，字节+字节应该定义为返回短，而 INT + INT 应该返回长，这两者都不是真实的。

我在什么地方听说过，这可能是性能相关的，但我不希望肯定地说。 （也许处理器通常只在32位和64位整数提供整数运算？）

无论哪种方式，它并没有真正的无论的为什么是这种情况 - 这是语言的只是规则

请注意，混合式赋值操作符有一个隐式转换回相关类型，所以你的可以的写：

 短X = 10;
短Y = 20;
X + = Y;
 

I have a code:

static short Sum(short a, short b)
        {
            return a + b;
        }

And it does not compile, saynig cannot convert 'int' to 'short'. I am maybe really tired today but I cannot see the issue!

解决方案

And it does not compile, saynig cannot convert 'int' to 'short'. I am maybe really tired today but I cannot see the issue!

It's just the way the language is defined. The + operator on integer types is defined for:

static uint op +(uint x, uint y)
static int op +(int x, int y)
static ulong op +(ulong x, ulong y)
static long op +(long x, long y)

Operands are promoted as required.

Now as for the reasons why it's defined that way - I don't know, to be honest. I don't buy the argument of "because it could overflow" - that would suggest that byte + byte should be defined to return short, and that int + int should return long, neither of which is true.

I've heard somewhere that it could be performance related, but I wouldn't like to say for sure. (Perhaps processors typically only provide integer operations on 32 and 64 bit integers?)

Either way, it doesn't really matter why it's the case - it's just the rules of the language.

Note that the compound assignment operators have an implicit conversion back to the relevant type, so you can write:

short x = 10;
short y = 20;
x += y;

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