Download The Math Class The Random Class

The Math Class
Some classes allow you to use their methods without creating an object of the class
first (with a constructor). The Math class is an example of this. We often use
methods of the Math class just by invoking them in our code.
First, add the following import statement to the top of your code:
import java.lang.Math;
The methods of the Math class that are included on the AP* exam:
Math.abs(int num)
Math.abs(double num)
Returns the absolute value
Math.pow(double num, double power)
Returns the value num raised to the
double num = 3;
specified power
double power = 2;
double num2 = Math.pow(num, power);
Math.random()
Returns a random number between 0.0
(inclusive) and 1.0 (exclusive)
Math.sqrt(double num)
double num = 2;
num2 = Math.sqrt(num); //returns 4
Returns the square root of num, which
must be positive
The Random Class
The Random class uses a pseudorandom number generator. First, add the
following import declaration:
import java.util.Random;
Then create an object of the class.
Random generator = new Random();
Use the nextInt() and nextDouble() methods to produce random numbers.
num1 = generator.nextInt(10); //from 0 to 9
num1 = generator.nextInt(10) + 1; //from 1 to 10