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PHP Exercises: Compute the sum of first n given prime numbers

PHP: Exercise-65 with Solution

Write a PHP program to compute the sum of first n given prime numbers.

Input: n ( n ≤ 10000). Input 0 to exit the program.

Pictorial Presentation:

PHP: Compute the sum of first n given prime numbers.

Sample Solution: -

PHP Code:

<?php
$max = 105000;
$arr = new \SplFixedArray($max + 1);
for ($i = 2; $i <= $max; $i++) {
    $arr[$i] = 1;
}
for ($i = 2, $len = sqrt($max); $i <= $len; $i++) {
    if (!$arr[$i]) {
        continue;
    }
    for ($j = $i, $len2 = $max / $i; $j <= $len2; $j++) {
        $arr[$i * $j] = 0;
    }
} 
while (($line = trim(fgets(STDIN))) !== '0') {
    $n = (int)$line;
    $result = 0;
    $cnt = 0;
    for ($i = 2; $i <= $max; $i++) {
        if ($cnt === $n) {
            break;
        } elseif ($arr[$i]) {
            $result += $i;
            $cnt++;
        }
    }
    echo "Sum of first ".$n." prime numbers:";
    echo $result, PHP_EOL;
}
?>

Sample Input:
25
0

Sample Output: 

Sum of first 25 prime numbers:1060

Flowchart:

Flowchart: Compute the sum of first n given prime numbers.

PHP Code Editor:

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Previous: Write a PHP program to replace a string "Python" with "PHP" and "Python" with " PHP" in a given string.
Next: Write a PHP program that accept a even number (n should be greater than or equal to 4 and less than or equal to 50000, Goldbach number) from the user and create a combinations that express the given number as a sum of two prime numbers. Print the number of combinations.

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PHP: Tips of the Day

Mutates the original array to filter out the values specified

Example:

<?php
function tips_pull(&$items, ...$params)
{
  $items = array_values(array_diff($items, $params));
  return $items;
}

$items = ['x', 'y', 'z', 'x', 'y', 'z'];
print_r(tips_pull($items, 'y', 'z'));
?>

Output:

Array
(
    [0] => x
    [1] => x
)