 Adding It All Up 
You'll remember how, in the first part of this tutorial, we used the + operator to add numbers and strings together. And just as you have the + operator for addition, JSP comes with a bunch of other arithmetic operators designed to simplify the task of performing mathematical operations.
The following example demonstrates the important arithmetic operators available in JSP:
<html>
<head>
</head>
<body>
<%!
// declare variables
int alpha = 25;
int beta = 5;
int sum, difference, product, quotient, remainder;
%>
<%
// perform operations
out.println("The sum of " + alpha + " and " + beta + " is " + (alpha + beta) + "<br>");
out.println("The difference of " + alpha + " and " + beta + " is " + (alpha  beta) + "<br>");
out.println("The product of " + alpha + " and " + beta + " is " + (alpha * beta) + "<br>");
out.println("The quotient after division of " + alpha + " and " + beta + " is " + (alpha / beta) + "<br>");
out.println("The remainder after division of " + alpha + " and " + beta + " is " + (alpha % beta) + "<br>");
%>
</body>
</html>
And here's the output:
''.preg_replace(array('/ /', '/ /'), array(' ', ' '), '
The sum of 25 and 5 is 30
The difference of 25 and 5 is 20
The product of 25 and 5 is 125
The quotient after division of 25 and 5 is 5
The remainder after division of 25 and 5 is 0
').''
As with all other programming languages, division and multiplication take precedence over addition and subtraction, although parentheses can be used to give a particular operation greater precedence. For example,
<%
out.println(10 + 2 * 4);
%>
returns 18, while
<%
out.println((10 + 2) * 4);
%>
returns 48.
In addition to these operators, JSP comes with the very useful autoincrement [++] and autodecrement [] operators, which you'll see a lot of in the next article. The autoincrement operator increments the value of the variable to which it is applied by 1, while the autodecrement operator does the opposite. Here's an example:
<%!
int x = 99;
%>
<%
// x = 99
out.println("Before increment, x = " + x + "<br>");
x++;
// x = 100
out.println("After increment, x = " + x);
%>
JSP also comes with a bunch of comparison operators, whose sole raison d'etre is to evaluate expressions and determine if they are true or false. The following table should make this clearer.
Assume x=4 and y=10
Operator What It Means Expression Result

== is equal to x == y False
!= is not equal to x != y True
> is greater than x > y False
< is less than x < y True
>= is greater than or equal to x >= y False
<= is less than or equal to x <= y True

How to do Everything with PHP & MySQL
How to do Everything with PHP & MySQL, the bestselling book by Melonfire, explains how to take full advantage of PHP's builtin support for MySQL and link the results of database queries to Web pages. You'll get full details on PHP programming and MySQL database development, and then you'll learn to use these two cuttingedge technologies together. Easytofollow sample applications include a PHP online shopping cart, a MySQL order tracking system, and a PHP/MySQL news publishing system.
Read more, or grab your copy now!

