PHP if, else and else if Conditional Statements

While writing programs/scripts, there will be scenarios where you would want to execute a particular statement only if some condition is satisfied. In such situations we use Conditional statements.

In PHP, there are 4 different types of Conditional Statements.

1. if statements
2. if...else statements
3. if...elseif...else statements
4. switch statement

We will cover the switch statements in the next tutorial.

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The if statement

When we want to execute some code when a condition is true, then we use if statement.

Syntax:

if(condition)
{
    // code to be executed if 'condition' is true
}

Here is a simple example,

<?php

$age = 20;

if($age <= 25)
{
    echo "You are not allowed to consume alchohol";
}
?>

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The if...else statement

When we want to execute some code when a condition is true, and some other code when that condition is false, then we use the if...else pair.

Syntax:

if(condition)
{
    // code to be executed if 'condition' is true
}
else 
{
    // code to be executed if 'condition' is false
}

Here is a simple example,

<?php

$age = 26;

if($age <= 25)
{
    echo "You are not allowed to consume alchohol";
}
else 
{
    echo "Enjoy the drinks";
}
?>

Enjoy the drinks

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The if...else...elseif statement

When we want to execute different code for different set of conditions, and we have more than 2 possible conditions, then we use if...elseif...else pair.

Syntax:

if(condition1)
{
    // code to be executed if 'condition1' is true
}
elseif(condition2)
{
    // code to be executed if 'condition2' is true
}
else
{
    /* code to be executed if both 'condition1'
     and 'condition2' are false */
}

Here is a simple example,

<?php
// speed in kmph
$speed = 110;

if($speed < 60)
{
    echo "Safe driving speed";
}
elseif($speed > 60 && $speed < 100)
{
    echo "You are burning extra fuel";
}
else 
{
    // when speed is greater than 100
    echo "Its dangerous";
}
?>

Its dangerous

In the example above, we have also used logical operator &&. Logical operators are very useful while writing multiple conditions together.

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