PHP Exercises: Compute sum of the prime numbers less than 100

PHP: Exercise-37 with Solution

Write a PHP program to compute the sum of the prime numbers less than 100.

Note: There are 25 prime numbers are there in less than 100.
2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97 and sum of all these numbers is 1060.

Sample Solution:

PHP Code:

<?php
// Array to store prime numbers
$primes = array();
// Flag to check if a number is prime
$is_prime_no = false;

// Loop to find the first 100 prime numbers
for ($i = 2; $i < 100; $i++) {
    $is_prime_no = true; 

    // Nested loop to check if $i is divisible by any number from 2 to $i/2
    for ($j = 2; $j <= ($i/2); $j++) {
        if ($i % $j == 0) {
            // If $i is divisible, it's not a prime number
            $is_prime_no = false;
            break;
        }
    }

    // If $i is a prime number, add it to the $primes array
    if ($is_prime_no) {
        array_push($primes, $i);
    }

    // If 100 prime numbers are found, exit the loop
    if (count($primes) == 100) {
        break;
    }
}

// Output the sum of the first 100 prime numbers
echo array_sum($primes) . "\n";

?>

Sample Output:

1060       

Flowchart:

PHP Code Editor:

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