Control statements
Control statements in PHP are fundamental programming constructs that enable you to control the flow of your PHP code based on certain conditions and to perform repetitive tasks using loops. These statements are crucial for implementing logic, making decisions, and controlling the execution of your PHP scripts.
Here’s an overview of the key control statements in PHP, along with explanations of their usage:
1.Conditional Statements:
Conditional statements are used to execute different blocks of code based on the evaluation of conditions.
(a)if Statement: Allows you to execute a block of code if a specified condition is true. If the condition is false, the code inside the if block is skipped.
if ($condition)
{
// Code to execute if $condition is true
}
(b).else Statement: Used in conjunction with if statements, it allows you to specify an alternative block of code to execute when the if condition is false.
if ($condition) { // Code to execute if $condition is true } else { // Code to execute if $condition is false }
(c).elseif Statement: Allows you to check multiple conditions in a sequence and execute different code blocks based on the first true condition encountered.
if ($condition1) { // Code to execute if $condition1 is true }
elseif ($condition2) { // Code to execute if $condition2 is true }
else { // Code to execute if none of the conditions are true }
(d).switch Statement: Used for more complex branching based on the value of a single variable, where different code blocks are executed depending on the variable’s value.
switch ($variable)
{ case ‘value1’: // Code for value1 break;
case ‘value2’: // Code for value2 break;
default: // Code to execute if no case matches }
2.Looping Statements:
Looping statements allow you to repeat a block of code multiple times.
(a).for Loop: Executes a block of code a specified number of times. It is commonly used when you know the number of iterations in advance.
for ($i = 0; $i < 5; $i++) { // Code to execute in each iteration }
(b).while Loop: Executes a block of code as long as a specified condition is true. It is used when the number of iterations is not known in advance.
while ($condition) { // Code to execute while $condition is true }
(c).do…while Loop: Similar to a while loop but always executes the code block at least once before checking the condition.
do { // Code to execute at least once } while ($condition);
(d).foreach Loop: Iterates over arrays or other iterable objects, simplifying the process of accessing each element in the collection.
$colors = [“red”, “green”, “blue”]; foreach ($colors as $color) { // Code to execute for each $color }
3.Branching Statements:
Branching statements are used to control the flow within loops and functions.
(a).break Statement: Allows you to exit a loop or switch statement prematurely. It is often used to exit a loop when a certain condition is met.
for ($i = 0; $i < 10; $i++) { if ($i == 5) { break; // Exit the loop when $i is 5 } }
(b).continue Statement: Skips the current iteration of a loop and proceeds to the next one. It is used when you want to bypass specific iterations without exiting the loop.
for ($i = 0; $i < 10; $i++) { if ($i == 5) { continue; // Skip the iteration when $i is 5 } }
(c).return Statement: Exits a function and optionally returns a value to the calling code. It is used to terminate the execution of a function and pass back a result.
function add($a, $b) { return $a + $b; // Exits the function and returns the result }
Control statements are essential for implementing decision-making logic and repetitive tasks in PHP, making it possible to create dynamic and interactive web applications by controlling the flow of your code.