Ø Conditional Structure
Conditional statement are the statement which are used when we want to check any condition between two variable.
PHP provides us with some kind of conditional statement as below.
- Simple If Statement
Generally this kind of statement are used when we want to check only the true condition. It will process only if the condition is true otherwise nothing.
Syntax
if(condition)
{
Code to be executed if condition is true
}
Example
<?php
$a=10;
$b=20;
if($a!=$b)
{
echo "a and b are not same value";
}
?>
- If – Else Statement
Use this statement if you want to execute some code if the condition is true and another code if the condition is false.
Syntax
if(condition)
{
Code to be executed if condition is true
}
else
{
Code to be executed if condition is false
}
Example
<?php
$m1=40;
$m2=60;
$m3=50;
if($m1>=40 && $m2>=40 && $m3>=40)
{
echo "Result : Pass";
}
else
{
echo "Result : Fail";
}
?>
- If – Else - if Statement
Use this statement if you want to select one of many blocks of code to be executed.
Syntax
If(condition1)
{
Code to be executed if condition is true
}
else If(condition2)
{
Code to be executed if condition is true
}
else If(condition_N)
{
Code to be executed if condition is true
}
else
{
Code to be executed if condition is false
}
Example
<?php
$str ="red";
if($str == "red")
{
echo "Stop";
}
else if($str == "yellow")
{
echo "Wait";
}
else
{
echo "Go";
}
?>
- Switch Statement
You should use the switch statement if you want to select one of many blocks of code to be executed.
Syntax
Switch(expression)
{
case 1:
Execute code block 1
break;
case 2:
Execute code block 2
break;
default:
code to be executed if n is different from case1 and case 2;
break;
}
- First we have a single expression n that is evaluated once
- The value of expression is then compared with the values for each case in the structure. If there is a match, the block of code associated with that case is executed.
- Use break to prevent the code from running into the next case automatically.
Example
<?php
$a=1;
switch($a)
{
case 1:
echo "January";
break;
case 2:
echo "February";
break;
case 3:
echo "March";
break;
default:
echo "Try again";
break;
}
?>
Ø Looping Structure
Very often when you write code, you want the same block of code to run over and over again in a row. Instead of adding several almost equal lines in a script we can use loops to perform a task like this.
In PHP there are three different kind of loops.
1.for loop
2.while loop
3.do while loop
- The for loop
Loops through a block of code a specified number of times. The for loop is used when you know in advance how many times the script should run.
Syntax
for(initialization; condition; increment or decrement)
{
Code to be executed
}
The for loop has three section initialization, condition, increment or decrement.
Initialization: means the variable is to be started with some values. This means starting value to be given to the variable.
Condition: condition section check the condition if the condition is true then code to be executed else executed the next statement after for loop.
Increment or decrement: to process the loop we have to either increment the variable or decrement the variable otherwise the loop will not process.
Example
<?php
for($a=1;$a<=10;$a++)
{
echo $a."<br/>";
}
?>
- The while loop
The while loop is used when you want the loop to execute and continue executing while the specified condition is true.
The increment of the number is done manually inside the loop.
Syntax
while(condition)
{
Code to be executed
Increment or decrement of the variable
}
Example
<?php
$a=1;
while($a<=10)
{
echo $a."<br/>";
$a=$a+1;
}
?>
- The do…while loop
The do while loop is a variant of the while loop. The loop will always execute a block of code once, and then it will repeat the loop as long as the specified condition is true.
This loop always be executed once, even if the condition is false, because the code are executed before the condition is tested.
Syntax
do
{
Code to be executed
}
while(condition);
Example
<?php
$a=1;
do
{
echo $a."<br/>";
$a=$a+1;
}
while($a<=10);
?>
- foreach statement
The foreach statement is used to look through arrays.
For every loop the value of the current array element is assign to $value and the array pointer is moved by 1, so on the next loop you will be looking at the next element.
Syntax
foreach(array as value)
{
Code to be executed
}
Example
<?php
$arr=array("one","two","three");
foreach($arr as $value)
{
echo "value is ".$value."<br/>";
}
?>
Output
Value is one
Value is two
Value is three
- foreach with key type value
The following example that will print the key and value of given array.
Example
<?php
$arr=array("one","two","three");
foreach($arr as $key=>$value)
{
echo "key is $key & value is ".$value."<br/>";
}
?>
Output
key is 0 & value is one
key is 1 & value is two
key is 2 & value is three
key is 1 & value is two
key is 2 & value is three
Posted By : Hemangi Zala
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