由网友(一枕星梦河)分享简介：如果我有一些code这样的：If i have some code like the following:short myShortA = 54;short myShortB = 12;short myShortC = (short)(myShortA - myShortB);这两个操作数都是短裤和它进入一个短...

如果我有一些code这样的：

If i have some code like the following:

short myShortA = 54;
short myShortB = 12;
short myShortC = (short)(myShortA - myShortB);

这两个操作数都是短裤和它进入一个短，为什么我一定要投它？

Both operands are shorts and it's going into a short so why do i have to cast it?

推荐答案

由于没有短 - 短操作符。这两个操作数提升为int类型。

Because there's no "short - short" operator. Both operands are promoted to int.

从C＃3规范的第7.7.5：

From section 7.7.5 of the C# 3 spec:

在predefined减法运算符   在下面列出。运营商所有   从x减去y。

The predefined subtraction operators are listed below. The operators all subtract y from x.   

整数加减：

Integer subtraction:

int operator –(int x, int y);
uint operator –(uint x, uint y);
long operator –(long x, long y); 
ulong operator –(ulong x, ulong y);

在checked上下文中，如果差   结果类型的范围外，   则会引发System.OverflowException。

In a checked context, if the difference is outside the range of the result type, a System.OverflowException is thrown.

（再有就是浮点减法。）

(And then there's floating point subtraction.)