Java和C＃中的char之间的区别（（char）-1的特殊问题）

Question

char x = (char)-1;

is valid in Java, but shows me the error ( Overflow in constant value computation )

Should I use a different datatype in C#?

Answer 1

The error occurs because C# is smarter about literals ("constant computation"). In C# one could do...

int x = -1;
char c = (char)x;
int y = c;
// y is 0xffff, as per Java

However, do note that 0xFFFF is an invalid Unicode character :)

Happy coding.

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Using unchecked will also "work":

unchecked {
  char x = (char)-1;
}

Answer 2

Here's the definition of the C# char type ; it's a 16-bit Unicode character, same as in Java . If you are just looking for a 16-byte signed value, then you might want a short .

For your reference, here is a list of the integral types available to you in C#.

You can also use an unchecked statement such as unchecked { char x = (char)-1; } unchecked { char x = (char)-1; } ; however, if it were me and I was, for instance, using -1 to represent an error value or some other marker, I would probably just use: char x = (char)0xFFFF; which gives you the same result, and a way of checking for an invalid value, without needing to circumvent the type check.