Prime Number Program

#include <stdio.h>
int main() {
int n, i, flag = 0;
printf("Enter a positive integer: ");
scanf("%d", &n);
for (i = 2; i <= n / 2; ++i) {
// condition for non-prime
if (n % i == 0) {
flag = 1;
break;
}
}
if (n == 1) {
printf("1 is neither prime nor composite.");
}
else {
if (flag == 0)
printf("This is a prime number.");
else
printf("This is not a prime number.");
}
return 0;
}

#include <iostream>
using namespace std;
int main()
{
int n, i;
bool isPrime = true;
cout << "Enter a positive integer: ";
cin >> n;
for(i = 2; i <= n / 2; ++i)
{
if(n % i == 0)
{
isPrime = false;
break;
}
}
if (isPrime)
cout << "This is a prime number";
else
cout << "This is not a prime number";
return 0;
}

import java.util.Scanner;
class PrimeCheck
{
public static void main(String args[])
{    
int temp;
boolean isPrime=true;
Scanner scan= new Scanner(System.in);
System.out.println("Enter a positive number:");
//capture the input in an integer
int num=scan.nextInt();
scan.close();
for(int i=2;i<=num/2;i++)
{
temp=num%i;
if(temp==0)
{
isPrime=false;
break;
}
}
//If isPrime is true then the number is prime else not
if(isPrime)
System.out.println(num + " is a Prime Number");
else
System.out.println(num + " is not a Prime Number");
}
}

# To take input from the user
num = int(input("Enter a positive integer: "))
# prime numbers are greater than 1
if num > 1:
# check for factors
for i in range(2,num):
if (num % i) == 0:
break
else:
print(num,"is a prime number")
# if input number is less than
# or equal to 1, it is not prime
else:
print(num,"is not a prime number")

function primeCheck($number){ 
if ($number == 1) 
return 0; 
for ($i = 2; $i <= $number/2; $i++){ 
if ($number % $i == 0) 
return 0; 
} 
return 1; 
} 
// Driver Code 
$number = 31; 
$flag = primeCheck($number); 
if ($flag == 1) 
echo "31 is a prime number."; 
else
echo "31 is Not a prime number."