Page 55 浮点类型造成非预期的不相等

using System.Diagnostics; namespace CH03 { class Program { static void Main(string[] args) { decimal decimalNumber = 4.2m; double doubleNumber1 = 0.1f * 42f; double doubleNumber2 = 0.1d * 42d; float floatNumber = 0.1f * 42f; Trace.Assert(decimalNumber != (decimal)doubleNumber1); System.Console.WriteLine("{0} != {1}", decimalNumber, (decimal)doubleNumber1); Trace.Assert((double)decimalNumber != doubleNumber1); System.Console.WriteLine("{0} != {1}", (double)decimalNumber, doubleNumber1); Trace.Assert((float)decimalNumber != floatNumber); System.Console.WriteLine("(float){0}m != {1}f", (float)decimalNumber, floatNumber); Trace.Assert(doubleNumber1 != (double)floatNumber); System.Console.WriteLine("{0} != {1}", doubleNumber1, (double)floatNumber); Trace.Assert(doubleNumber1 != doubleNumber2); System.Console.WriteLine("{0} != {1}", doubleNumber1, doubleNumber2); Trace.Assert(floatNumber != doubleNumber2); System.Console.WriteLine("{0}f != {1}d", floatNumber, doubleNumber2); Trace.Assert((double)4.2f != 4.2d); System.Console.WriteLine("{0}f != {1}d", (double)4.2f, 4.2d); Trace.Assert(4.2f != 4.2d); System.Console.WriteLine("{0}f != {1}d", 4.2f, 4.2d); System.Console.ReadKey(true); } } } using System.Diagnostics; namespace CH03 { clas