Boolean Expressions

This chapter introduces relational and logical operators. It also discusses the use of these operators to write Boolean expressions.

12. Complete Boolean Expressions


// check that the income is within range for the 28% bracket
if ( income >=24000 && income <= 58150  )
  System.out.println("In the 28% bracket." );
  System.out.println("Time for an audit!" );

Complete Boolean Expressions

AND combines the results of two boolean values. In this example, the boolean values are produced by relational expressions, like this:

income >= 24000  &&  income <= 58150
------------- ---------------
relational relational
expression expression

Each relational expression must be complete. The following is a MISTAKE:

income >= 24000  &&      <= 58150
------------- ---------------
relational not a complete
expression relational

This is INCORRECT because the characters that follow && do not form a complete relational expression. The Java compiler would not accept this.

Question 12:

Here is an incorrect boolean expression that is intended to test if a person's age is between 21 and 35.

    age >= 21 && <= 35
Fix the boolean expression.