Interesting behaviour of type “decimal” in C#

Question

If we declare padding as const decimal, the padding is not working.

mymoney = 1.2 and your money = 1.20, how can this behavior be explained?

class Progra         


        

Answer 1

As an accompaniment to Jon's answer, below is the IL produced from your code. As he mentioned, mymoney was never added.

.method private hidebysig static void  Main(string[] args) cil managed
{
  .entrypoint
  // Code size       61 (0x3d)
  .maxstack  6
  .locals init ([0] valuetype [mscorlib]System.Decimal balance,
           [1] valuetype [mscorlib]System.Decimal padding,
           [2] valuetype [mscorlib]System.Decimal mymoney,
           [3] valuetype [mscorlib]System.Decimal yourmoney)
  IL_0000:  nop
  IL_0001:  ldc.i4.s   12
  IL_0003:  ldc.i4.0
  IL_0004:  ldc.i4.0
  IL_0005:  ldc.i4.0
  IL_0006:  ldc.i4.1
  IL_0007:  newobj     instance void [mscorlib]System.Decimal::.ctor(int32,
                                                                     int32,
                                                                     int32,
                                                                     bool,
                                                                     uint8)
  IL_000c:  stloc.0
  IL_000d:  ldc.i4.0
  IL_000e:  ldc.i4.0
  IL_000f:  ldc.i4.0
  IL_0010:  ldc.i4.0
  IL_0011:  ldc.i4.2
  IL_0012:  newobj     instance void [mscorlib]System.Decimal::.ctor(int32,
                                                                     int32,
                                                                     int32,
                                                                     bool,
                                                                     uint8)
  IL_0017:  stloc.1
  IL_0018:  ldloc.0
  IL_0019:  ldc.i4.2
  IL_001a:  call       valuetype [mscorlib]System.Decimal [mscorlib]System.Decimal::Round(valuetype [mscorlib]System.Decimal,
                                                                                          int32)
  IL_001f:  stloc.2
  IL_0020:  ldloc.0
  IL_0021:  ldloc.1
  IL_0022:  call       valuetype [mscorlib]System.Decimal [mscorlib]System.Decimal::op_Addition(valuetype [mscorlib]System.Decimal,
                                                                                                valuetype [mscorlib]System.Decimal)
  IL_0027:  ldc.i4.2
  IL_0028:  call       valuetype [mscorlib]System.Decimal [mscorlib]System.Decimal::Round(valuetype [mscorlib]System.Decimal,
                                                                                          int32)
  IL_002d:  stloc.3
  IL_002e:  ldloc.2
  IL_002f:  call       void [mscorlib]System.Console::WriteLine(valuetype [mscorlib]System.Decimal)
  IL_0034:  nop
  IL_0035:  ldloc.3
  IL_0036:  call       void [mscorlib]System.Console::WriteLine(valuetype [mscorlib]System.Decimal)
  IL_003b:  nop
  IL_003c:  ret
} // end of method Program::Main

To produce the IL (i.e. if you want to look under the hood in the future), just run ILDASM from a VS command prompt, then load your executable and double-click on the method that you would like to look at.