PHP Documentation - if statement in PHP

linuxStat PHP Documentation

Conditional execution of PHP code

The PHP if statement provides a mechanism to execute
a block of PHP code only if a condition is true.

The if statement has the following structure:

if (condition 1) {
PHP Code 1
}

PHP Code 1 enclosed by the braces { } is executed
if condition 1 enclosed by the parentheses ( ) is TRUE.

If condition 1 is FALSE, PHP Code 1 is not executed.

Example 7.1:

I have 1005 Intel (INTC) shares in my Fidelity Investments
broker account. I bought them at $18.05 a share. I keep track
of my profit or loss in a PHP program using a variable named
$currentPrice. The value of this variable is the current price of
1 share of Intel stock.

I use an if statement to determine when I am ready to sell my INTC shares.

$currentPrice = 17.80; // Line 1
if ($currentPrice < 18.05 ) { // Line 2
 print "Do not take a loss. Do not sell your INTC shares. ";
}

Since the condition within the parenthess ( ) in Line 2 is TRUE,
the print statement is executed.

The program in Example 7.1 embedded in an HTML document:

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/transitional.dtd">
<html>
<head>
<meta http-equiv=Content-Type content="text/html; charset=us-ascii">
<title>Executed on Dell Server, Intel Processor, created on HP laptop</title>
</head>
<body bgcolor="#0F243E" text="#FFFF00" lang=EN-US>

<?php
# An example of how PHP if statement works.
$currentPrice = 17.80;
if ($currentPrice < 18.05) {
print "Do not take a loss. Do not sell your INTC shares. ";
}
?>

</body>
</html>

Click the following link to execute the above PHP program
by my server's PHP interpreter.

Try the above example

Example 7.2:

$age = 9; // Line 1
if (($age > 12) && ($age <= 19)) { // Line 2
print "Marvin K. Mooney, you are a teenager. ";
}

Since the condition within the parenthess ( ) in Line 2 is FALSE,
the print statement is NOT executed.

The program in Example 7.2 embedded in an HTML document:

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/transitional.dtd">
<html>
<head>
<meta http-equiv=Content-Type content="text/html; charset=us-ascii">
<title>Executed on Dell Server, Intel Processor, created on HP laptop</title>
</head>
<body bgcolor="#0F243E" text="#FFFF00" lang=EN-US>

<?php
# An example of how PHP if statement works.
$age = 9;
if (($age > 12) && ($age <= 19)) {
print "Marvin K. Mooney, you are a teenager. ";
}
?>

</body>
</html>

Click the following link to execute the above PHP program
by my server's PHP interpreter.

Try the above example Next Index