BEI - if Statements Control Flow (Lesson)

if Statements Control Flow

Introduction

Flow of control is the order in which statements are executed. In the programs that we have written so far, our code has been executed one line at a time in the order that it was written. This order is called linear - meaning that programs are executed one statement at a time, one after another.

What if we wanted to change that? There are times when we may want one block of code to be executed several times instead of just once. For example, in our previous unit we looked at generating the roll of a die by creating a random number generator. How would you write code that would show five or ten rolls of the dice?

Conditional/Selection Statement

Conditional or selection statements allow us to choose which statement of code will be executed next. This allows statements of code to be repeated or skipped altogether. To do this in Java, we use if statements, if-else statements, and switch statements. The AP Exam, and this course, will cover if and if-else statements.

Decision Making

Now that we can repeat or skip lines of code, we need to make the decision when to do that. This is done with boolean expressions. Code can be written with a boolean expression to decide on whether a statement should be executed. Boolean expressions will either be evaluated true or false. If the expression is true, then the code will be executed. If it is false, then the code will be skipped.