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Functions

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Working WithFunctions

Functions are useful becausethey make it possible totreat a related group of PHPstatements as a single unit.

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Defining Functions

The lines of a code that make upa function are called thefunction definition.

The syntax for defining afunction is as follows

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Parameters

Parameters are placedwithin the parentheses thatfollow the function name.

A parameter is a variablethat is used within afunction.

You can also assign defaultvalues to a parameter.

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Parameters

function computeX($number){

echo $number;

}==================

=============

functionsample($num1=10,$num2=5){

echo

$num1

;

echo

$num2

;

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Parameter

You can specify default valuesfor parameters.

If you specify default valuesfor parameters, thoseparameters are optional.You can call the function without

specifying those parameters.The default value will be used.

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Parameters

function sayHello($color,$size=2,$face=Arial){

echo Hello

;

}

sayHello(red);sayHello(blue,5);

sayHello(green,5,Courier);

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Calling Function

functionprintCompanyName($name){

echo

$name

;

}printCompanyName(Course

Technology);

Note: Unlike variables,

function are case insensitive.This means that you can callprintCompanyName()function with any of the ff.

statements.

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Returning Values

$returnValue= aveNumber(1,2,3);

function aveNumber($a,$b,$c){

$sum=$a+$b+$c;

$result=$sum/3;return $result;

}

A return statement is astatement that returns a value tothe statement that called thefunction, which calculates the

average of three numbers.

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UnderstandingVariable Scope

Variable Scope: refers towhere in your program adeclared variable can be used.

A global variable is one that isdeclared outside a function andis available to all parts of yourprogram.

A local variable is declared insidea function and is only availablewithin the function in which it is

declared.

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Activity1. Create a function named greetings, include three

parameters inside it. When the function namegreetings is called, it should print the words:Hi, Hello, Goodbye!

Save your file as functionGreetings.html

2. Create a function named calculateSquare includeone parameter inside it named number, as you

call the name of your function it should displaythe square of the number. Try to pass aparameter value of 9 to the variable number.

3. Create a function named equivalentGrade, includetwo parameter inside named rawScore and

totlScore. When the function is called the ff.output is displayed in the browser:

Given: rawScore=50totlscore=100

A raw score of 50 is equivalent to 75%.