Multiplying a double value by 100.0 introduces rounding errors?

Question

This is what I am doing, which works 99.999% of the time:

((int)(customerBatch.Amount * 100.0)).ToString()

The Amount value is a double. I am trying to write the value out in pennies to a text file for transport to a server for processing. The Amount is never more than 2 digits of precision.

If you use 580.55 for the Amount, this line of code returns 58054 as the string value.

This code runs on a web server in 64-bit.

Any ideas?

Answer 1

You should really use decimal for money calculations.

((int)(580.55m * 100.0m)).ToString().Dump();