You only use the M
for a numeric literal, when you cast it's just:
decimal dtot = (decimal)doubleTotal;
Note that a floating point number is not suited to keep an exact value, so if you first add numbers together and then convert to Decimal
you may get rounding errors. You may want to convert the numbers to Decimal
before adding them together, or make sure that the numbers aren't floating point numbers in the first place.