Comparing quantities

 

In addition to the standard arithmetic operators, Java allows us to compare numerical values using a set of familiar constructs.  These are the relational operators and are as follows:

 

            <     is less than

      >     is greater than

      >=    is greater than or equal to

      <=    is less than or equal to

      !=    is not equal to

      ==    is equal to

 

The result of a relational expression, as opposed to an arithmetic one, can only be either true or false.  Both of these truth values are reserved words in Java and are referred to as Boolean values.   So if we type the statement

 

      System.out.println(3 != 5);   // does 3 not equal 5?

 

will output true, while the statement System.out.println(3 != 3); will output false.  Such statements can also include arithmetic expressions.  An example:

 

      System.out.println(10 % 3 == 12 / 8);

 

To understand how this statement will be evaluated, it’s useful to know that relational operators have lower precedence than arithmetic operators.  This means that the modulus subexpression will be evaluated first, yielding 1, then the division which also results in 1. Finally the comparison 1 == 1 is carried out, so the output will be the Boolean value true.