Question

Write a PHP function to check if a number in input is prime or not. Add all the necessary checks to the input. Note: A prime number (or a prime) is a natural number greater than 1 that has no positive divisors other than 1 and itself, Duh.

Answer 1

<?php

// Utility function for checking whether number is prime or not

function checkIfPrime($numValue){
if ($numValue == 1)
return 0;
  
for ($i = 2; $i <= sqrt($numValue); $i++){
if ($numValue % $i == 0)
return 0;
}
return 1;
}
  
// Enter number which you want to check
$numValue = 31;

// Checking Valid Natural Number
if($numValue > 0){
$isPrime = checkIfPrime($numValue);
if ($isPrime == 1)
echo "$numValue is Prime";
else
echo "$numValue is Not Prime";
}
else{
echo "Please Enter Natural Number";
}

?>