Question

Consider following program:

static void Main (string[] args) {
    int i;
    uint ui;

    i = -1;
    Console.WriteLine (i == 0xFFFFFFFF ? "Matches" : "Doesn't match");

    i = -1;
    ui = (uint)i;
    Console.WriteLine (ui == 0xFFFFFFFF ? "Matches" : "Doesn't match");

    Console.ReadLine ();
}

The output of above program is:

Doesn't match
Matches

Why the first comparison fails when unchecked conversion of integer -1 to unsigned integer is 0xFFFFFFFF? (While the second one passes)

Answer 1

Your first comparison will be based on longs … since 0xFFFFFFFF is not an int value 🙂
Try to write

Console.WriteLine( (long)i == 0xFFFFFFFF ? "Matches" : "Doesn't match" );

and you will get a cast is redundant message