• This is a program that will take int values entered at the command line, determine the prime and composite values, store them each in a list then print each list
• This program was above and beyond anything I “needed” to do but I wanted to have it in my portfolio. It covers a lot of attributes. Doubly linked lists, pointers, libraries, selection etc.

#include<stdlib.h>
#include"doubly.h"
//This is a program to determine all the prime and and composite numbers between 2 and a user defined positive integer
// Primes and composites will be be stored in two seperate linked lists
// This program could technically test any group with an upper bound as high as the highest range of unsigned int
// but it seems to have issues with extremely high numbers
 
int main()
{
	unsigned int x, i, value, primeFlag = 0; // x,i, and primeFlag are for my nested for loop(testing for prime/comp)
	List *myListPrime, *myListComp;// A list for each type.
	Node *tmp;// only purpose is to allow access to the functions in my doubly library, not needed for anything else in this instance
	myListPrime = (List *)malloc(sizeof(List));// mallocing the lists
	myListComp = (List *)malloc(sizeof(List));
	myListPrime->start = myListPrime->end = myListComp->start = myListComp->end = tmp = NULL;// Starting them off as empty
 
	printf("Please enter a whole number value greater than 2: ");
	scanf("%ud", &value);
 
	for(x=2; x<=value; x++)// nitty gritty, a nested for loop for testing, this goes from x until we reach the user entered value
	{
		for(i=2; i<=x; i++)// this takes each number from 2 until user entered value and then tests it with each integer from 2 until itself
		{
			if(x % i == 0 && i != x)//  this is how I test for composite, if any value has no remainder when divided by any lesser value
			{						// then it is a proven composite
				newNode(myListComp, tmp, x);// so the value is added to the comp list
				primeFlag = 0;// this prevents the comp value from being added to the prime list
				break;// this stops the loop as there is no need to continue once value is proven as comp
			}			
			else
			{
				primeFlag = 1;// if there is remainder then we set primeFlag = to 1, as there is a POSSIBILITY it is a prime
			}
		}
		if(primeFlag == 1)// if the entire loop finished without reaching break then that means it must be prime
		{
			newNode(myListPrime, tmp, x); // add value to prime list
		}
 
 
	}
	printf("Composites: \n");  // these next lines now print the composite list and the prime list
	printList(myListComp, tmp);
	printf("Primes: \n");
	printList(myListPrime, tmp);
 
	return (0);
}