Functions in PHP
1. Function to print “Hello PHP”
<?php
function greet(){
echo "Hello PHP";
}
greet();
?>
2. Function to add two numbers
<?php
function add($a, $b){
return $a + $b;
}
echo "Sum: " . add(10, 20);
?>
3. Function to find square of a number
<?php
function square($num){
return $num * $num;
}
echo "Square: " . square(5);
?>
4. Function with default parameter values
<?php
function greetUser($name = "Guest"){
echo "Welcome, $name";
}
greetUser();
echo "<br>";
greetUser("Boby");
?>
5. Function to calculate factorial
<?php
function factorial($n){
$fact = 1;
for($i=1; $i<=$n; $i++){
$fact *= $i;
}
return $fact;
}
echo "Factorial: " . factorial(5);
?>
6. Function to return largest of two numbers
<?php
function largest($a, $b){
return ($a > $b) ? $a : $b;
}
echo "Largest: " . largest(15, 25);
?>
7. Function to check prime number
<?php
function isPrime($num){
if($num <= 1) return false;
for($i=2; $i<$num; $i++){
if($num % $i == 0){
return false;
}
}
return true;
}
$num = 7;
echo isPrime($num) ? "$num is Prime" : "$num is Not Prime";
?>
8. Function to reverse a string
<?php
function reverseString($str){
return strrev($str);
}
echo reverseString("PHP");
?>
9. Function to count vowels in a string
<?php
function countVowels($str){
$count = 0;
$str = strtolower($str);
for($i=0; $i<strlen($str); $i++){
if(in_array($str[$i], ['a','e','i','o','u'])){
$count++;
}
}
return $count;
}
echo "Vowels: " . countVowels("Hello PHP");
?>
10. Function to check palindrome string
<?php
function isPalindrome($str){
return ($str == strrev($str));
}
$text = "madam";
echo isPalindrome($text) ? "Palindrome" : "Not Palindrome";
?>
11. Demonstrate local and global variables
<?php
$x = 10;
function test(){
global $x;
$y = 20;
echo "Global x: $x <br>";
echo "Local y: $y";
}
test();
?>
12. Recursive function for factorial
<?php
function factorial($n){
if($n == 0) return 1;
return $n * factorial($n - 1);
}
echo "Factorial: " . factorial(5);
?>
13. Recursive Fibonacci function
<?php
function fibonacci($n){
if($n == 0) return 0;
if($n == 1) return 1;
return fibonacci($n-1) + fibonacci($n-2);
}
for($i=0; $i<10; $i++){
echo fibonacci($i) . " ";
}
?>
14. Function to calculate area of circle
<?php
function areaCircle($radius){
return 3.1416 * $radius * $radius;
}
echo "Area: " . areaCircle(7);
?>
15. Function to return sum of array elements
<?php
function arraySum($arr){
return array_sum($arr);
}
$numbers = [10, 20, 30];
echo "Sum: " . arraySum($numbers);
?>
16. Function to convert Celsius to Fahrenheit
<?php
function celsiusToFahrenheit($c){
return ($c * 9/5) + 32;
}
echo "Fahrenheit: " . celsiusToFahrenheit(30);
?>
17. Function to check if number is even
<?php
function isEven($num){
return ($num % 2 == 0);
}
echo isEven(10) ? "Even Number" : "Odd Number";
?>
18. Function to capitalize first letter of each word
<?php
function capitalizeWords($str){
return ucwords($str);
}
echo capitalizeWords("hello php programming");
?>
19. Function to generate multiplication table
<?php
function table($num){
for($i=1; $i<=10; $i++){
echo "$num x $i = " . ($num * $i) . "<br>";
}
}
table(5);
?>
20. Function to return length of string
<?php
function stringLength($str){
return strlen($str);
}
echo "Length: " . stringLength("PHP Programming");
?>
21. Function to validate email format
<?php
function validateEmail($email){
return filter_var($email, FILTER_VALIDATE_EMAIL) !== false;
}
$email = "test@example.com";
echo validateEmail($email) ? "Valid Email" : "Invalid Email";
?>
22. Function to generate random password
<?php
function generatePassword($length = 8){
$chars = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789!@#";
return substr(str_shuffle($chars), 0, $length);
}
echo "Generated Password: " . generatePassword(10);
?>
23. Function to check strong password
<?php
function isStrongPassword($password){
return preg_match('/^(?=.*[A-Z])(?=.*[a-z])(?=.*\d).{8,}$/', $password);
}
echo isStrongPassword("Test@123") ? "Strong Password" : "Weak Password";
?>
24. Function to remove duplicate values from array
<?php
function removeDuplicates($arr){
return array_unique($arr);
}
$data = [1,2,2,3,4,4];
print_r(removeDuplicates($data));
?>
25. Function to sort associative array by values
<?php
function sortByValue($arr){
asort($arr);
return $arr;
}
$students = ["Amit"=>85, "Ravi"=>75, "Sita"=>90];
print_r(sortByValue($students));
?>
26. Function to calculate compound interest
<?php
function compoundInterest($p, $r, $t){
return $p * pow((1 + $r/100), $t);
}
echo "Amount: " . compoundInterest(1000, 5, 2);
?>
27. Function to sanitize user input
<?php
function sanitizeInput($data){
return htmlspecialchars(trim($data));
}
$input = "<script>alert('hack')</script>";
echo sanitizeInput($input);
?>
28. Function to check if string contains substring
<?php
function contains($string, $search){
return strpos($string, $search) !== false;
}
echo contains("Hello PHP", "PHP") ? "Found" : "Not Found";
?>
29. Function to flatten multidimensional array
<?php
function flattenArray($array){
$result = [];
foreach($array as $value){
if(is_array($value)){
$result = array_merge($result, flattenArray($value));
} else {
$result[] = $value;
}
}
return $result;
}
$data = [1, [2,3], [4,[5,6]]];
print_r(flattenArray($data));
?>
30. Function to calculate age from DOB
<?php
function calculateAge($dob){
$birthDate = new DateTime($dob);
$today = new DateTime();
return $today->diff($birthDate)->y;
}
echo "Age: " . calculateAge("2000-05-10");
?>
31. Function to generate slug (SEO-friendly URL)
<?php
function generateSlug($text){
$text = strtolower(trim($text));
$text = preg_replace('/[^a-z0-9]+/', '-', $text);
return trim($text, '-');
}
echo generateSlug("Learn PHP Programming Fast!");
?>
32. Function to paginate array data
<?php
function paginate($data, $page, $limit){
$offset = ($page - 1) * $limit;
return array_slice($data, $offset, $limit);
}
$data = range(1,50);
print_r(paginate($data, 2, 10));
?>
33. Function to encrypt password (hashing)
<?php
function hashPassword($password){
return password_hash($password, PASSWORD_DEFAULT);
}
echo hashPassword("mypassword");
?>
34. Function to verify hashed password
<?php
function verifyPassword($password, $hash){
return password_verify($password, $hash);
}
$hash = password_hash("12345", PASSWORD_DEFAULT);
echo verifyPassword("12345", $hash) ? "Match" : "Not Match";
?>
35. Function to find second largest number in array
<?php
function secondLargest($arr){
rsort($arr);
return $arr[1];
}
$data = [10, 20, 50, 40];
echo "Second Largest: " . secondLargest($data);
?>
36. Function to check palindrome number
<?php
function isPalindromeNumber($num){
return $num == strrev($num);
}
echo isPalindromeNumber(121) ? "Palindrome" : "Not Palindrome";
?>
37. Function to merge and sort arrays
<?php
function mergeSortArrays($a, $b){
$merged = array_merge($a, $b);
sort($merged);
return $merged;
}
print_r(mergeSortArrays([5,2], [3,1]));
?>
38. Function to count word frequency
<?php
function wordFrequency($text){
$words = explode(" ", strtolower($text));
return array_count_values($words);
}
print_r(wordFrequency("php is easy php is powerful"));
?>
39. Function to validate mobile number (India)
<?php
function validateMobile($number){
return preg_match('/^[6-9]\d{9}$/', $number);
}
echo validateMobile("9876543210") ? "Valid" : "Invalid";
?>
40. Function to create JSON response (API-style)
<?php
function jsonResponse($data){
header("Content-Type: application/json");
return json_encode($data);
}
$data = ["status"=>"success", "message"=>"Data fetched"];
echo jsonResponse($data);
?>