In this chapter we will show you how to create your own functions.
To keep the script from being executed when the page loads, you can put it into a function.
A function will be executed by a call to the function.
You may call a function from anywhere within a page.
Create a PHP Function
A function will be executed by a call to the function.
Syntax
function functionName()
{
code to be executed;
}
PHP function guidelines:
- Give the function a name that reflects what the function does
- The function name can start with a letter or underscore (not a number)
Example
A simple function that writes my name when it is called:
<html>
<body>
<?php
function writeName()
{
echo "Mohammed Kateregga";
}
echo "My name is ";
writeName();
?>
</body>
</html>
Output :
My name is Mohammed Kateregga
Adding parameters
To add more functionality to a function, we can add parameters. A parameter is just like a variable.
Parameters are specified after the function name, inside the parentheses.
Example 1
The following example will write different first names, but equal last name:
<html>
<body>
<?php
function writeName($fname)
{
echo $fname . " Kateregga.<br />";
}
echo "My name is ";
writeName("Mohammed");
echo "My sister's name is ";
writeName("Halma");
echo "My brother's name is ";
writeName("Abdulhameed");
?>
</body>
</html>
Output :
My name is Mohammed Kateregga.
My sister's name is Halma Kateregga.
My brother's name is Abdulhameed Kateregga.
Example 2
The following function has two parameters:
<html>
<body>
<?php
function writeName($fname,$punctuation)
{
echo $fname . " Kateregga" . $punctuation . "<br />";
}
echo "My name is ";
writeName("Mohammed",".");
echo "My sister's name is ";
writeName("Halma","!");
echo "My brother's name is ";
writeName("Abdulhameed","?");
?>
</body>
</html>
Output:
My name is Mohammed Kateregga.
My sister's name is Halma Kateregga!
My brother's name is Abdulhameed Kateregga?
Return values
To let a function return a value, use the return statement.
Example
<html>
<body>
<?php
function add($x,$y)
{
$total=$x+$y;
return $total;
}
echo "1 + 16 = " . add(1,16);
?>
</body>
</html>
Output:
1 + 16 = 17
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