PHP function to check whether a number is prime or not

In this tutorial, we will discuss the concept of the PHP function to check whether a number is prime or not

In this post, we are going to learn how to check whether a number is prime or not, using a user-defined function in PHP programming language with Example programs.

Prime number

The number that can be divided by 1 and itself. it is called a prime number

for Example 2,3,5,7,11,13…

PHP example to check whether a Number is Prime or Not

Check the prime number using a function– method 1

In this program, The user declares and initializes variables as parameters. When calling the function with an argument, it will check whether the given number is a prime number or not, using the function in the PHP language.

Program 1

<?php
function checkPrime($num){
    //function definition
for($i=2; $i<$num; $i++){
  if($num%$i==0){
  return 0;
  }
}
return 1;
}
$x=checkPrime(29);
//Call the function with argument
if($x==0){
echo "this is not a prime number.";
//print if the number is not prime
}else{
echo "this is a prime number.";
//print if the number is prime
}

?>

When the above code is executed, it produces the following result

this is a prime number.

Check the prime number using a function– method 2

Program 2

<?php
function checkPrime($num){
    //function definition
$n=0;
for($i=2; $i<($num/2+1); $i++){
  if($num%$i==0){
  $n++;
  break;
  }
}

if($n==0){
echo $num." is a prime number.";
//print if the number is a prime
}else{
echo $num." is not a prime number.";
//print if the number is not prime
}
}
checkPrime(17);
//Call the function with argument
?>

When the above code is executed, it produces the following result