# PHP Exercises: Print the number of prime numbers which are less than or equal to a given integer

## PHP: Exercise-52 with Solution

Write a PHP program to print the number of prime numbers which are less than or equal to a given integer.

**Input:**

n (1 ≤ n ≤ 999,999) .

**Pictorial Presentation: **

**Sample Solution: **-

**PHP Code:**

```
<?php
$a = array_fill(0, 1000000, true);
$a[0] = $a[1] = false;
for($i = 2; $i * $i < 1000000; $i++){
if(!$a[$i]) continue;
for($j = $i * $i; $j < 1000000; $j += $i){
$a[$j] = false;
}
}
$sum = array_fill(0, 1000000, 0);
for($i = 1; $i < 1000000; $i++){
$sum[$i] += $sum[$i - 1];
if($a[$i]) $sum[$i]++;
}
while(fscanf(STDIN, "%d", $n)){
echo "Number of prime numbers which are less than or equal to n: ";
echo $sum[$n] . "\n";
}
?>
```

Sample Output:

Sample Input: 50 Number of prime numbers which are less than or equal to n: 15

**Flowchart: **

**PHP Code Editor:**

**Have another way to solve this solution? Contribute your code (and comments) through Disqus.**

**Previous:** Write a PHP program to compute the amount of the debt in n months.

**Next:** Write a PHP program to compute the radius and the central coordinate (x, y) of a circle which is constructed by three given points on the plane surface.

**What is the difficulty level of this exercise?**

Test your Programming skills with w3resource's quiz.

## 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 )

**Weekly Trends**- Java Basic Programming Exercises
- SQL Subqueries
- Adventureworks Database Exercises
- C# Sharp Basic Exercises
- SQL COUNT() with distinct
- JavaScript String Exercises
- JavaScript HTML Form Validation
- Java Collection Exercises
- SQL COUNT() function
- SQL Inner Join
- JavaScript functions Exercises
- Python Tutorial
- Python Array Exercises
- SQL Cross Join
- C# Sharp Array Exercises