If not, it executes a second if-else statement. The first if-else statement determines if temperature's value is negative. Java lets you chain multiple if-else statements together for situations where you need to choose one of multiple statements to execute:Ĭhaining works by executing a subsequent if-else statement whenever the current if statement's Boolean expression evaluates to false. (The conditional operator is also sometimes known as the ternary operator.) Instead, it can only return one of two values of the same type. However, this operator cannot be used to execute alternate statements. The conditional operator ( ?:) is similar to an if-else statement. ('You have ' + (55 - age) + ' years to go until early retirement.') Conditional operator vs if-else The following example demonstrates an if-else statement that tells someone who is less than 55 years old how many years are left until early retirement: The if-else statement is similar to the if statement, but it includes the reserved word else, followed by a statement to execute when the Boolean expression is false. Here's the syntax for the if-else statement: The statement executed depends on whether the expression evaluates to true or false. The if-else statement evaluates a Boolean expression and executes a statement. This time, you should not observe the message in the output. Now, suppose you assign 25 to age and then re-execute /2 (or the equivalent snippet number in your session). Executing /2 causes jshell to list and then execute this snippet, and the same message is output. I observe that the if statement snippet has been assigned 2 in my session. Pressing Enter after the last snippet line causes jshell to immediately execute the snippet.Įxecute /list to list all snippets. > continuation prompt when you enter a multiline snippet. Notice that the jshell> prompt changes to the. You are or were eligible for early retirement.

> ('You are or were eligible for early retirement.') Next, enter the first example if statement (without the curly braces surrounding its body): Restart jshell and then introduce an age variable (of type int) that's initialized to 55: Many people prefer to wrap any simple statement that follows the if statement in braces, effectively converting it to an equivalent compound statement:Īlthough the braces clarify what is being executed by the if statement, I believe that the indentation provides this clarity, and that the braces are unnecessary. ('You are or were eligible for early retirement.')

When the age variable contains a value of 55 or greater, if executes (.) to output the message: The following example demonstrates the if statement. The if statement starts with reserved word if and continues with a parenthesized Boolean expression, which is followed by the statement to execute when the Boolean expression evaluates to true. The if statement has the following syntax: The simplest of Java's decision statements is the if statement, which evaluates a Boolean expression and executes another statement when this expression evaluates to true. Additionally, a new switch expressions feature has been added to Java 12. Java supports the if, if-else, and switch decision statements. Also, if a student's grade on an algebra test is greater than 85 percent, congratulate the student for doing well otherwise, recommend that the student study harder for the next test. For example, if a salesperson sells more than 500 items this month, give the salesperson a bonus. Making decisions: if, if-else, and switchĭecision statements let applications choose between multiple paths of execution. Notice that snippet #7 has been removed, and a snippet #15 has been added thanks to the /12 command. Finally, we entered /list to re-list all snippets. Next, we entered /drop 7 to delete snippet #7 (no more age += 10 snippet). We then entered /list 13 to list snippet #13, which increments age. Here we've entered /12 to re-execute snippet #12, which outputs the contents of text.

A compound statement is a sequence of simple and other compound statements located between open- and close-brace characters (.

A simple statement is a single standalone instruction for performing a task it must be terminated with a semicolon character ( ).A statement can be expressed as a simple or a compound statement: Java applications evaluate expressions in the context of statements, which are used for tasks such as declaring a variable, making a decision, or iterating over statements.

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