I'm doing a conversion from Fortran 90 to C++ and I have run into a small (or large, I'm not sure) problem. In the Fortran there are some calculations and they use the REAL data type, which is equivalent to double. My problem is that the Fortran seems to do these calculations a bit more precisely because I lose some data to rounding errors (or so it seems when I output the values after the calculations) in the C++ version of the code. Im wondering if there is a way to force the C code to keep all the data to the 10th decimal point or if its just the output that is messing it up. The reason I don't think it is the output statements messing up is because at the end of a few functions I have a variable that is about .7 off from the Fortran equivalent. Any help would be appreciated, and I would post some code, but it would be a lot to go through, so I'm not sure what code would be helpful.