PHP Introduction - Lecture #9

PHP FUNCTIONS

Hello All... welcome every one. I'm going to start PHP lectures for Very Beginners, who wants to learn PHP from very beginning. No matter if you do not have any basic programming concept. If you follow my tutorials I hope you will surely get some how good knowledge of PHP.

Today our Topic is

FUNCTIONS

We use functions for avoiding repetition of code again and again. We write our code within a certain block and name that block, so whenever we need the same code we just call that name not the whole code to be repeated again.

Much like variables function name is declared with same patterns but not starts with $ sign. Here is how we create a function.

<?php

            function function_name(){

            echo “this is function example”;

}

function_name();

?>

First of all write function keyword, besides that give a name to this function with open and close braces then start and close the curly brackets and inside that curly brackets you can write your code whatever you want, I have just echo a statement further you can write loops, if conditions or anything else.

Now to display what is written inside the function body we call that function, by writing just the name of the function. But remember call the function outside the function body. How much times you call name of function so many times the result will come out. Look for another example.

<?php

            function addition(){

            $num1 = 20;

            $num2 = 30;

            echo $num1 + $num2;

}

addition();

?>

The result will be 50, if again you call function name such as,

addition();

addition();

it will generate `5050`. Similarly in this way you can put your every code just like conditions, operators, loops inside the function and for output just call the function name.

From the top you are declaring the function and in the bottom you are calling the function for output.

  ð Passing Values To a Function

If you want to give dynamic values for output you can pass values to a function by putting the values between the parentheses when you call the function.

Look for an example

<?php

            Function pass_value ($var1, $var2){

            echo $var1 + $var2;

}

pass_value(20,30);

pass_value(40,50);

pass_value(50,50);

?>

Firstly declare any variables you want. In echo statement just write the code you want to execute and the values you will be giving within the braces while calling the function and no matter how many times you call the function and whether you give same values or different the result will be according to your values you are given.

Above declared variables within function braces are called as parameters, and the values given in last while calling function are called Arguments.

Note that sequence and the quantity of the Parameters and Arguments should be the same otherwise it’ll generate the wrong result.

Thanks Guys. Any thing missing or any question from this topic you can comment below, I will be trying to solve and answer your question.

Our Next topic will be `Built-in Functions `.

Good Luck J