Android™ How to Program, Second Edition

Floating-Point Number Precision and Memory Requirements

Variables of type float represent single-precision floating-point numbers and can represent up to seven significant digits. Variables of type double represent double-precision floating-point numbers. These require twice as much memory as float variables and provide 15 significant digits—approximately double the precision of float variables. For the range of values required by most programs, variables of type float should suffice, but you can use double to “play it safe.” In some applications, even double variables will be inadequate. Most programmers represent floating-point numbers with type double. In fact, Java treats all floating-point numbers you type in a program’s source code (such ...