C++ Precision: String to Double

Question

I am having a problem with precision of a double after performing some operations on a converted string to double.

#include    
#include <         


        

Answer 1

The "problem" here is simply that 34.38 cannot be exactly represented in double-precision floating point. You should read this article which describes why it's impossible to represent decimal values exactly in floating point.

If you were to examine "34.38 * 100" in hex (as per "format hex" in MATLAB for example), you'd see:

40aadc0000000001

Notice the final digit.