Lecture 2

Conditional Statement

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Conditional Statements in PHP

Conditional Statements are used for decision making. Different actions are

performed for different decision. PHP has the following conditional statements

If statement: executes a code only if a condition is met.If – else statement: executes a code if a condition is true

and if false, executes another code.If – else if – else statement: if the first condition is not

true, another condition is tested, if all condition fails, then a code is executed.Switch Statement: selects a block of code out of several

blocks to be executed.

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IF Statement

If statement executes a code only if a condition is met. It has the syntax:

If (condition){do something}For example <?php$image = “car”;If ($image == “car”){print ‘<img src = “images/work. jpg” alt = “a red car”

height = “150” width =“150” >’;}?>

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So here we have used both the if statement and the comparison

operator = = (equal) . It checks if the value assigned to the variable

$image is car, if it is, the image is displayed and if not, nothing is

displayed.Assuming we change the value of $image to

be moon. Nothing will be displayed because the condition is false.

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If-else statement

Assuming we want to do something else if a condition is false, the if-else statement is used.

It has the syntaxIf (condition){do something}else{Do something else}

For example, lets try using another comparison operator.

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practical 5.2Given x = 5, write a program that will check if the

value of x is an odd number or an even number.To do this, we will first declare a variable x and then

store the value 5 in it. Then we will write the if – else statement. We also know that every

even number is divisible by 2 without remainder and every odd number will have a

remainder when divided by 2. to test this condition, we will use the modulus operator to check if

dividing the value of x by 2 gives a remainder or not then a comparison operator to check.

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solution<?php$x = 5; if ($x%2 !=0){print “X is an odd number”;}else{print “X is an even number”;}

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If-else if -elseAssuming we have more than two conditions to test.

The if – else if –else statement is used. It has the syntaxif (condition){Do something;}else if (another condition){Do something;}else{Do something else;}

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Switch statementAssuming we have more than two conditions to test, multiple if

statement will be more complex to handle this. The best way will be to use a switch statement. It chooses one block of

code out of several blocks to execute if the condition for that code evaluates to true. It

has the syntax.Switch (n){case x:Do something;Break;Case x:Do something;Break;Default:Do something;}Where n is the variable name and x is the value of the variable we are

testing.The break is used to prevent the code from automatically running into the next

block of codeThe default is used to handle a situation when all case fails or evaluates to false.

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practical 5.3Write a program to output the class of a grade depending on

the Grade of the user.<?php$grade =“A” ;Switch ($grade){Case “A”:echo “Excellent”;break;Case “B”:Echo “very good”;Break;Case “C”:Echo “Average”;Break;Default:Echo “Please Enter a valid grade”;}