Split double into two int, one int before decimal point and one after

This is how you could do it:

string s = inputValue.ToString("0.00", CultureInfo.InvariantCulture);
string[] parts = s.Split('.'); 
int i1 = int.Parse(parts[0]);
int i2 = int.Parse(parts[1]);

Manipulating strings can be slow. Try using the following:

double number;

long intPart = (long) number;
double fractionalPart = number - intPart;

What programming language you want to use to do this? Most of the language should have a Modulo operator. C++ example:

double num = 10.5;
int remainder = num % 1