c# why does math.floor return a double code example

Example: c# floor double

double[] values = {7.03, 7.64, 0.12, -0.12, -7.1, -7.6};
Console.WriteLine("  Value          Ceiling          Floor\n");
foreach (double value in values)
   Console.WriteLine("{0,7} {1,16} {2,14}",
                     value, Math.Ceiling(value), Math.Floor(value));
// The example displays the following output to the console:
//         Value          Ceiling          Floor
//
//          7.03                8              7
//          7.64                8              7
//          0.12                1              0
//         -0.12                0             -1
//          -7.1               -7             -8
//          -7.6               -7             -8