PHP Exercises: Create a string like "aababcabcd" from a given string "abcd"

PHP Basic Algorithm: Exercise-30 with Solution

Write a PHP program to create a string like "aababcabcd" from a given string "abcd".

Sample Solution:

PHP Code :

<?php
// Define a function that generates a string by concatenating substrings from the input string
function test($s)
{
    // Initialize an empty string to store the result
    $result = "";

    // Iterate through the string
    for ($i = 0; $i < strlen($s); $i++) {
        // Append substrings from the beginning up to the current index
        $result .= substr($s, 0, $i + 1);
    }

    // Return the final result
    return $result;
}

// Test the function with different input strings
echo test("abcd")."\n";
echo test("abc")."\n";
echo test("a")."\n";
?>

Explanation:

• Function Definition:
• The test function takes a single parameter, $s, which is a string. It builds and returns a new string by concatenating progressively longer substrings from $s.
• Initialize Result Variable:
• An empty string $result is initialized to store the concatenated substrings.
• Iterate Through String:
• A for loop iterates through each character of the string $s, from index 0 to strlen($s) - 1.
• Append Substrings:
• For each index $i, a substring from the beginning of $s up to the character at position $i is appended to $result.
• substr($s, 0, $i + 1) extracts this substring.
• Return Final Result:
• After the loop, $result contains the cumulative substrings and is returned.

Output:

aababcabcd
aababc
a

Flowchart:

PHP Code Editor:

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