Sum of Digits at Even and Odd Places in PHP

Given a Number, the task is to sum the Digit of Even and Odd places using PHP. Calculating the sum of digits at even and odd places in a number is a common programming task. Here, we will cover all approaches with detailed explanations and code examples.

Approach 1: Sum of Digits at Even and Odd Places using a Loop

One approach is to convert the number to a string, iterate over each digit, and calculate the sum based on whether the digit’s position is even or odd.

PHP

<?php

function evenOddDigitSum($num) {
    $numStr = (string) $num;
    $evenSum = 0;
    $oddSum = 0;

    for ($i = 0; $i < strlen($numStr); $i++) {
        if ($i % 2 == 0) {
            $evenSum += $numStr[$i];
        } else {
            $oddSum += $numStr[$i];
        }
    }

    return ["even" => $evenSum, "odd" => $oddSum];
}

// Driver code
$num = 123456;
$sums = evenOddDigitSum($num);

echo "Even Places Digit Sum: " . $sums["even"] . "\n";
echo "Odd Places Digit Sum: " . $sums["odd"];

?>

Output

Even Places Digit Sum: 9
Odd Places Digit Sum: 12

In this approach, we convert the number to a string to easily access each digit. We then iterate over each digit, checking if its position (index) is even or odd and updating the respective sums.

Approach 2: Sum of Digits at Even and Odd Places using Mathematical Operations

Another approach is to extract digits from the number using mathematical operations and then calculate the sums.

PHP

<?php

function evenOddDigitSum($num) {
    $evenSum = 0;
    $oddSum = 0;

    while ($num > 0) {
        $digit = $num % 10;
        if ($digit % 2 == 0) {
            $evenSum += $digit;
        } else {
            $oddSum += $digit;
        }
        $num = (int) ($num / 10);
    }

    return ["even" => $evenSum, "odd" => $oddSum];
}

// Driver code
$num = 123456;
$sums = evenOddDigitSum($num);

echo "Even Places Digit Sum: " . $sums["even"] . "\n";
echo "Odd Places Digit Sum: " . $sums["odd"];

?>

Output

Even Places Digit Sum: 12
Odd Places Digit Sum: 9