PHP Lecture 02.pptx PHP Lecture 02 .pptx

Conditional Statements
if Statement
• if statement executes some code if one condition is true.
if (condition) {
code to be executed if condition is true;
}
if...else Statement
• The if....else statement executes some code if a condition is true and another
code if that condition is false.
if (condition) {
code to be executed if condition is true;
} else {
code to be executed if condition is false;
}

Conditional Statements (Cont…)
if...elseif....else Statement
• The if....elseif...else statement executes different codes for more than
two conditions.
if (condition) {
code to be executed if this condition is true;
} elseif (condition) {
code to be executed if this condition is true;
} else {
code to be executed if all conditions are false;
}

Conditional Statements (Cont…)
switch Statement
• Use the switch statement to select one of many blocks of code to be
executed.
switch (n) {
case label1:
code to be executed if n=label1;
break;
case label2:
break;
case label3:
break;
...
default:
code to be executed if n is different from all labels;
}

Loops
• Loops execute a block of code while the specified condition is true.
while Loop
<?php
$x = 1;
while($x <= 5) {
echo $x ," ";
$x++;
}
?>

Loops (Cont…)
do...while Loop
• The do...while loop will always execute the block of code once, it
will then check the condition, and repeat the loop while the specified
condition is true.
<?php
$x = 10;
do {
echo $x ." ";
$x++;
} while ($x <= 5);
?>

Loops (Cont…)
for Loop
• The for loop is used when you know in advance how many times the
script should run.
<?php
for ($x = 0; $x <= 5; $x++) {
echo $x. " ";
}
?>

Loops (Cont…)
foreach Loop
• The foreach loop works only on arrays, and is used to loop through each
key/value pair in an array.
• Syntax
foreach ($array_name as $variable_name) {
code to be executed;
}
• Example
<?php
$colors = array("Apple", "Orange", "Mango");
foreach ($colors as $value) {
echo "$value "; }
?>

Functions
• PHP has more than 1000 built-in functions.
• Besides the built-in PHP functions, we can create our own functions.
• A function is a block of statements that can be used repeatedly in a
program.
• A function will not execute immediately when a page loads.
• A function will be executed by a call to the function.

Creating a User Defined Function
• Syntax
function functionName() {
code to be executed;
}
• A function name can start with a letter or underscore (not a number).
• Function names are NOT case-sensitive.
• Example
<?php
function display() {
echo "Welcome to PHP";
}
display(); // call the function
?>

Function Arguments
• Information can be passed to functions through arguments.
• Arguments are specified after the function name, inside the
parentheses. Separate multiple arguments with a comma.
<?php
function display($msg) {
echo $msg;
}
display("Welcome to PHP"); // call the function
?>

Default Argument Value
• If we call the function display() without arguments it takes the default
value as argument:
<?php
function display($msg="Hello")
{
echo $msg." ";
}
display("Welcome to PHP"); // call the function
display();
?>

Returning values
• To let a function return a value, use the return statement.
• Value is returned back to the calling function/location.
<?php
function add($a, $b) {
$c = $a + $b;
return $c;
}
$result= add(5, 10);
echo $result. " ";
echo add(2,5);
?>

PHP Lecture 02.pptx PHP Lecture 02 .pptx

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