在C＃中，整数文字是什么类型？

Question

I just notice if i pass a value such as 1 in a function parameter it will work if it excepts int, long and i assume the others. However if i do int i = value, it doesnt. I was wondering, what type is it?

Answer 1

(1).GetType().ToString() //is System.Int32

Answer 2

Take a look at the integer literals specification :

The type of an integer literal is determined as follows:

• If the literal has no suffix, it has the first of these types in which its value can be represented: int, uint, long, ulong.
• If the literal is suffixed by U or u, it has the first of these types in which its value can be represented: uint, ulong.
• If the literal is suffixed by L or l, it has the first of these types in which its value can be represented: long, ulong.
• If the literal is suffixed by UL, Ul, uL, ul, LU, Lu, lU, or lu, it is of type ulong.

Answer 3

You can suffix literal integers to make the type explicit, otherwise the value will be implicitly interpreted as though it were the target type (assuming it doesn't overflow the target).

var myLong = 123L;
var myInt = 123;
var myByte = (byte)123; // i'm not aware of a suffix for this one

// unsigned variants
var myULong = 123UL;
var myUInt = 123U;

Answer 4

据我了解，编译器将在编译时使用类型提示来确定文字的类型。

Answer 5

The type is determined.

If you have this function:

public void SomeFunc( long i );

and you call it like this:

SomeFunc (1);

Then C# will see this '1' as being a long.

Answer 6

整数文字是int每默认的，但因为有一个从隐式转换int至long ，你仍然可以调用它采取的方法long与int 。