JAVA Expressions

What is an expression?

Anything that computes to a different value:

This            =            That

Expression 1              Expression 2



An expression can contain different types of mathematical operators - in Java the different operators you can use include:

                                                            +     addition
                                                            -      subtraction
                                                            *     multiplication
                                                            /     division
                                                           %    modulus or remainder
                                                           ()     parentheses


These operators will be dependent on what types of numbers are used, for example if you use only integer-type number variables, then the answer to  7/2 would be  3  (the full answer will not round but be cutoff to the whole number value) if you used floating type number variables the answer would be the full 3.5

The % can be used to obtain the remainder in this case 7/2 = 3 remainder 1 so a 7%2 would return the result of 1

The % can be useful for determining if a value is even or odd or to test if one integer is evenly divisible by another or not.


If a floating point type number (3.5) is combined in an expression with an integer type number the result will be a floating type number.

 
( ) parentheses are used as in standard math formulas to determine the order of operations in an expression

Expression Shortcuts

You can combine a few terms together when you want to update a variable to a new value that includes an operator on itself, for example:

 

cost = cost +1000;       OR        cost  +=  1000;    

 

You can quickly increment a variable by or decrease a variable by one:

minutes = minutes + 1     OR    ++minutes      OR     minutes++

 

minutes = minutes - 1    OR    --minutes    OR    minutes--