Menu
This is a follow up question. So, Java store's integers in two's-complements and you can do the following:
int ALPHA_MASK = 0xff000000;
In C# this requires the use of an unsigned integer, uint, because it interprets this to be 4278190080 instead of -16777216.
My question, how do declare negative values in hexadecimal notation in c#, and how exactly are integers represented internally? What are the differences to Java here?
928
A hexadecimal value is int as long as the value fits into int and for larger values it is unsigned , then long , then unsigned long etc. See Section 6.4. 4.1 of the C standard. Just as the accepted answer states.
A hexadecimal integer literal begins with the 0 digit followed by either an x or X, followed by any combination of the digits 0 through 9 and the letters a through f or A through F. The letters A (or a) through F (or f) represent the values 10 through 15, respectively.
A signed integer is a 32-bit datum that encodes an integer in the range [-2147483648 to 2147483647]. An unsigned integer is a 32-bit datum that encodes a nonnegative integer in the range [0 to 4294967295].
Obviously they are signed integers like +34, -15, -23,and +17. These numbers along with their sign have to be represented in a computer using only binary notation orbits. The simplest way of representing a signed number is the sign magnitude(SM) method.
C# (rather, .NET) also uses the two's complement, but it supports both signed and unsigned types (which Java doesn't). A bit mask is more naturally an unsigned thing - why should one bit be different than all the other bits?
In this specific case, it is safe to use an unchecked cast:
int ALPHA_MASK = unchecked((int)0xFF000000);
To "directly" represent this number as a signed value, you write
int ALPHA_MASK = -0x1000000; // == -16777216
Hexadecimal is not (or should not) be any different from decimal: to represent a negative number, you need to write a negative sign, followed by the digits representing the absolute value.
54
If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With
