In Visual C++ i wrote the following sample in a C++ program:

float f1 = 42.48f;
double d1 = 42.48;
double d2 = f1;

I compiled the program with Visual Studio 2005. In the debugger i see the following values:

f1  42.480000   float
d1  42.479999999999997  double
d2  42.479999542236328  double

d1 by my knowledege is OK, but d2 is wrong.

The problem occurs as well with /fp=precise as with /fp=strict as with /fp=fast.

Whats the problem here? Any hint how to avoid this Problem? This leads to serious numerical problems.