/*****************************************************************/
// File    : primenum.c
// Purpose : Checks whether the given number is PRIME or NOT a PRIME.
// Author  : Nanda Kishor K N                                    
// Mail Id : knnkishor@yahoo.com, nandakishorkn@rediffmail.com   
// Website : www.c4swimmers.esmartguy.com ( WEB MASTER )   
// Group   : c4swimmers@yahoogroups.com   ( MODERATOR )          
/*****************************************************************/

#include<stdio.h>
#include<math.h>
/*
   Name      :   main()
   Purpose   :   This is the main function that accepts the number and checks whether the 
                 given number is prime or not. Uses the built-in sqrt() function defined in math.h file
   Parameter :   None
*/

main()
{
	// Variable Declarations & Initialization
	// Naming conventions are used like all integer variables 
	int iNum,iFlag=1,iIdx; // Set the Flag
     
	printf("Enter number : ");
    scanf("%d",&iNum);
     
	// Check whether the given number n, which is divisible by 2,3,4,...,sqrt(n)
	// If the number is divisible then it is NOT a PRIME number
	// Otherwise it is a PRIME number
	for (iIdx = 2; iIdx <= (int)sqrt(iNum); iIdx++)
	{
        if (iNum % iIdx == 0)
		{
            iFlag=0; // Reset the Flag & terminate the loop
			break;
		}
	}
     
	// Verify the flag status and print the given number as PRIME or NOT a PRIME
	if (iFlag != 0)
       printf("It's a PRIME number\n");
	else
       printf("\nIt's NOT a PRIME number\n");
     
	return 0;
}   // End of main() program