Cochrane Wrote:If you do

Code:

float foo = 2.0

the finished program will load the number as a double and then convert it to a float, which is slower than

Code:

float foo = 2.0f

where the number will be loaded directly as float.

Well in cases like that, as long as you compile with optimizations on (i.e. release mode), any compiler worth its salt will precompute known constant conversions as far as possible at compile time.

And things are a bit complicated in the float/double world, this link explains things better than I can:
http://cpptips.hyperformix.com/cpptips/flt_dbl