Sams Teach Yourself Java™ in 24 Hours, Sixth Edition

if Statements

The most basic way to test a condition in Java is by using an if statement. The if statement tests whether a condition is true or false and takes action only if the condition is true.

You use if along with the condition to test, as in the following statement:

if (account < 0) {    System.out.println("Account overdrawn; you need a bailout");}

The if statement checks whether the account variable is below 0 by using the less than operator <. If it is, the block within the if statement is run, displaying text.

The block only runs if the condition is true. In the preceding example, if the account variable has a value of 0 or higher, the println statement is ignored. Note that the condition you test must be surrounded by parentheses, ...