PHP Exercises: Compute and print sum of two given integers

PHP: Exercise-54 with Solution

Write a PHP program to compute and print sum of two given integers (more than or equal to zero). If given integers or the sum have more than 80 digits, print "overflow".

Pictorial Presentation:

Sample Solution: -

PHP Code:

<?php
fscanf(STDIN, '%d', $N);
for ($i = 0; $i < $N; $i++) {
    fscanf(STDIN, '%s', $a);
    fscanf(STDIN, '%s', $b);
    if (max(strlen($a), strlen($b)) > 80) {
        echo "overflow\n";
        continue;
    }
    $arr = array_fill(0, 81, 0);
    $a = sprintf('%081s', $a);
    $b = sprintf('%081s', $b);
    for ($j = 80; $j > 0; $j--) {
        $n = $arr[$j] + $a[$j] + $b[$j];
        if ($n >= 10) {
            $arr[$j] = substr($n, 1);
            $arr[$j - 1] += 1;
        } else {
            $arr[$j] = $n;
        }
    }
    $result = preg_replace('/^0+(\d+)$/', '$1', implode('', $arr));
    if (strlen($result) > 80) {
        echo "overflow\n";
    } else {
        echo $result, PHP_EOL;
    }
}
?>

Sample Output:

46
overflow
overflow
overflow
overflow
...
overflow
overflow
overflow

Flowchart:

PHP Code Editor:

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