Example to calculate a square root of 900.0

Math.sqrt(900.0)

Note all Math Methods are static! Static classes are NOT instantiated. So "Math" methods are available for use with explicit creating an object. Math is part of java.lang package, which is automatically imported by the compiler.

abs(x) -absolute value

ceil(x) - rounds x to the smallest integer not less than x

cos(x) - cosine

exp(x) - exponential method e^x

floor(x) - rounds x to the largest integer not greater than x

log(x) - natural logarithm of x (base e)

max(x, y) - larger of x and y

min(x, y) - smaller of x and y

pow(x, y) - x raised to the power of y

sin(x) - sine of x

sqrt(x) - square root

tan(x) - tangent of x

The Math class also includes constants

Math.PI (3.1415926535979323846)

Math.E (2.7182818284590452354)

To create a random number between 0 and 1 (not including 1)

double randomReal;

randomReal = Math.random();

To create an integer between 1 and 6 suitable for a result of a dice throw.

int die;

die = (int) (Math.random()*6) + 1

Note: You should also look at the Random class and tips from the Sun web site. http://developer.java.sun.com/developer/JDCTechTips/2001/tt0925.html

For each of the primitive data types in Java provides a corresponding "wrapper" class. At times you need to treat simple data types as objects. This is particularly true when we look at Collections. The use of primitive data types is the main area where Java departs from being a "pure" Object Oriented language.

These wrapper classes also feature a number of utility methods. Generally, these methods handle various tasks that you would otherwise write yourself. Become familiar with these methods.

Integer anInteger = new Integer(5); -> Create an Integer from an int

int anint = anInteger.intValue(); -> Obtain the int value of an Integer

int anint = Integer.parseInt("5"); -> Obtain the int value of a String

String aString = anInteger.toString() -> String representation of a Integer.