Job Ready Java

Lesson 10Adding Randomness to Your Programs

We often want the ability to produce unpredictable behavior in our applications: to simulate rolling a die or flipping a coin in a game, for example. In this lesson, we will examine the use of the Random class to do just that.

LEARNING OBJECTIVES

By the end of this lesson, you will be able to:

• Initialize a Random object
• Use a Random object to generate random integers from any minimum to any maximum
• Employ random integers to select a value from an array
• Generate double values from any minimum to any maximum using a Random object
• Apply random values to a coin flip (or model any other probability) as a boolean value

INITIALIZING THE RANDOM OBJECT

Doing things in the same way every time is important at times, but every now and again a bit of unpredictably is needed. In those situations, we use Random, a class whose entire job is to mix things up.

We have to construct Random before we can use it, but afterward, we've got a whole virtual box of crazy, random options. Let's look at a couple of the interesting things you can do with Random.

Including the Random Class

By including an import of the Java Random utility package, you can use a Random class in your programs. This package is included by adding an import statement to the top of your listing with the name of the package. This is similar to what you did to include Scanner in a previous lesson.

import java.util.Random;

The Random class provides useful methods for automatically ...