Max HEX value for long type

Question

I have ported Java code to C#. Could you please explain why I have compile-time error in the follow line (I use VS 2008):

    private long l = 0xffffffffffffffff         


        

Answer 1

0xffffffffffffffff is larger than a signed long can represent.

You can insert a cast:

 private long l = unchecked( (long)0xffffffffffffffffL);

Since C# uses two's complement, 0xffffffffffffffff represents -1:

private long l = -1;

Or declare the variable as unsigned, which is probably the cleanest choice if you want to represent bit patterns:

private ulong l = 0xffffffffffffffffL;
private ulong l = ulong.MaxValue;

The maximal value of a singed long is:

private long l = 0x7fffffffffffffffL;

But that's better written as long.MaxValue.