Print Prime Numbers from 1 to 100 in PHP using For loop | While loop

Print prime numbers from 1 to 100 in PHP using for loop and while loop.

In this article, you will learn how to print prime numbers from 1 to 100 in PHP using for loop and while loop.

Example

You should have knowledge of the following topics in PHP programming to understand this program:

• PHP For loop
• PHP While loop

Sample of Prime Numbers

In this article, we solve this problem using two methods:

1. Using the for loop
2. Using the while loop

Source Code

<?php
// Print Prime Numbers from 1 to 100 in PHP using For loop

$x = 60;
echo "------The prime numbers from 1 to ".$x." are------\n\n";

for ($i = 0; $i < $x; $i++) {
    
    // There are niether prime nor composite if as skip 0 and 1 number
    if ($i == 1 || $i == 0)
        continue;
    
    $f = 1;
    
    for ($j = 2; $j < intval($i / 2) + 1; $j++) {
        if ($i % $j == 0) {
            $f = 0;
            break;
        }
    }
    
    // If f = 1 means i is prime number and f = 0 means i is not prime number
    if ($f == 1)
        echo $i." ";
}
echo "\n";

?>

Run Program

Output

Explanation

In this given program, we have taken input from the variable $x = 60 to generate prime numbers up to 60.

Then we applied simple calculation via for loop to check every number of range between 1-60 to find the prime numbers.

If any number is divided by only 1 & itself and which number is divisible by any numbers it means these type numbers are called prime numbers.

 After the whole calculation, this will return these numbers:  2 3 5 7 11 13 17 19 23 29 31 37 41 43 47 53 59, It's the final output of the above program.

Print Prime Numbers from 1 to 100 in PHP using While loop

<?php
// Print Prime Numbers from 1 to 100 in PHP using While loop

$x = 60;
echo "------The prime numbers from 1 to ".$x." are------\n\n";

$i = 0;
while ($i < $x) {
    
    // There are niether prime nor composite if as skip 0 and 1 number
    if ($i == 1 || $i == 0) {
        $i++;
        continue;
    }
    
    $f = 1;
    
    $j = 2;
    while ($j < intval($i / 2) + 1) {
        if ($i % $j == 0) {
            $f = 0;
            break;
        }
        $j++;
    }
    
    // If f = 1 means i is prime number and f = 0 means i is not prime number
    if ($f == 1)
        echo $i." ";

    $i++;
}
echo "\n";

?>

Run Program