FloatingPoint is the standard way to represent non-integer numbers in computers. FloatingPoint is works by representing numbers in a manner resembling scientific notation, with a mantissa and an exponent, along with a bit to indicate sign. Historically, FloatingPoint math has been significantly slower than integer math, particularly in machines without specialized FloatingPoint hardware, but all modern desktop processors include fast FloatingPoint units.
FloatingPoint numbers in C code are created by using the types
For more information about FloatingPoint math, see http://en.wikipedia.org/wiki/Floating_point