2.27 Jb0230: java oop: flow of control

Revised: Mon Mar 28 15:04:52 CDT 2016

This page is included in the following Books:

• Programming Fundamentals with Java
• Object-Oriented Programming (OOP) with Java

Table of contents

• Preface
  • Viewing tip
    • Figures
    • Listings
• Introduction
  • Flow of control
  • The while statement
  • The if-else statement
  • The switch-case statement
  • The for loop
  • The for-each loop
  • The do-while loop
  • The break and continue statements
  • Unlabeled break and continue
  • Labeled break and continue statements
    • Labeled break statements
    • Labeled continue statements
  • The return statement
  • Exception handling
• Looking ahead
• Miscellaneous

Preface

Java supports several different statements designed to alter or control the logical flow of the program. This module explores those statements.

Viewing tip

I recommend that you open another copy of this module in a separate browser window and use the following links to easily find and view the Figuresand Listings while you are reading about them.

Figures

• Figure 1 . Statements that support flow of control.
• Figure 2 . Syntax of a while statement.
• Figure 3 . Syntax of an if-else statement.
• Figure 4 . Syntax of a switch-case statement.
• Figure 5 . Syntax of a for loop.
• Figure 6 . Syntax of a do-while loop.
• Figure 7 . Syntax of a labeled statement.
• Figure 8 . An empty return statement.
• Figure 9 . Returning a value from a method.

Listings

• Listing 1 . Sample Java while statement.
• Listing 2 . A program that won't compile.
• Listing 3 . Another program that won't compile.
• Listing 4 . A program that will compile.
• Listing 5 . Another program that will compile.
• Listing 6 . The program named switch1.java.
• Listing 7 . The program named switch2.java.

Introduction

The first step

The first step in learning to use a new programming language is usually to learn the foundation concepts such as variables, types, expressions,flow-of-control, etc. This module concentrates on flow-of-control .

Flow of control

What is flow of control?

Java supports several different kinds of statements designed to alter or control the logical flow of the program.

The ability to alter the logical flow of the program is often referred to as Flow of Control .

Statements that support flow of control

Figure 1 lists the statements supported by Java for controlling the logical flow of theprogram.

The while statement

We've seen the while statement in earlier modules. Several of the programs in earlier modules contained a while statement designed to control the logical flow of the program.