Question

Possible Duplicate:
Extract decimal part from a floating point number in C

I would like retrieve the decimal part of a double in the most efficient way.

Something like this:

double a = 1.5;
double decimal_part = a -1 ; // decimal_part = 0.5

How retrieve and store in a variable in a really efficient way the .5 (decimal part of a) ?

Answer 1

Use modf function:

double integer_part;
double decimal_part = modf(a, &integer_part);