PHP Exercises: Check whether the first two characters and last two characters of a given string are same

PHP Basic Algorithm: Exercise-80 with Solution

Write a PHP program to check whether the first two characters and last two characters of a given string are same.

Sample Solution:

PHP Code :

<?php
// Define a function named 'test' that checks if the first two characters of a string
// are equal to the last two characters of the same string
function test($s1)
{ 
    // Use substr to extract the first two characters of $s1
    $firstTwo = substr($s1, 0, 2);
    
    // Use substr to extract the last two characters of $s1
    $lastTwo = substr($s1, strlen($s1) - 2, 2);
    
    // Check if the first two characters are equal to the last two characters
    return $firstTwo == $lastTwo;
}

// Test the 'test' function with different strings, then display the results using var_dump
var_dump(test("abab"));
var_dump(test("abcdef"));
var_dump(test("xyzsderxy"));
?>

Explanation:

• Function Definition:
• The function test is defined with one parameter:
• $s1: the input string to check.
• Extract First Two Characters:
• The first two characters of the string $s1 are extracted using substr:
• $firstTwo = substr($s1, 0, 2);
• Extract Last Two Characters:
• The last two characters of the string $s1 are extracted using substr:
• $lastTwo = substr($s1, strlen($s1) - 2, 2);
• Comparison:
• The function checks if the first two characters ($firstTwo) are equal to the last two characters ($lastTwo):
• return $firstTwo == $lastTwo;
• It returns true if they are equal, otherwise it returns false.

Output:

bool(true)
bool(false)
bool(true)

Flowchart:

PHP Code Editor:

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