﻿ PHP Exercise: Compute the sum of first n given prime numbers - w3resource

# 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: 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: PHP Code Editor:

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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
(
 => x
 => x
)
```