Delete all prime nodes from a singly linked list in c

C program for Delete all prime nodes from a singly linked list. Here problem description and explanation.

/*
    C program for
    Delete all prime nodes 
*/
#include <stdio.h>
#include <stdlib.h>

// Linked List LinkNode
struct LinkNode
{
	int data;
	struct LinkNode *next;
};
// Singly linked list 
struct SingleLL
{
	struct LinkNode *head;
};
// Returns the new linked list
struct SingleLL *newLinkedList()
{
	// Create new linked list
	struct SingleLL *sll = (struct SingleLL *)
	malloc(sizeof(struct SingleLL));
	if (sll == NULL)
	{
		printf("Memory overflow\n");
	}
	else
	{
		sll->head = NULL;
	}
	return sll;
}
// Handles the request of adding new node at end of linked list
void addNode(struct SingleLL *sll, int data)
{
	// Create dynamic node
	struct LinkNode *node = (struct LinkNode *)
	malloc(sizeof(struct LinkNode));
	if (node == NULL)
	{
		// Handle memory overflow 
		printf("Memory overflow to Create LinkNode\n");
		return;
	}
	else
	{
		// Set initial node value
		node->data = data;
		node->next = NULL;
	}
	if (sll->head == NULL)
	{
		// First node in linked list
		sll->head = node;
	}
	else
	{
		struct LinkNode *temp = sll->head;
		// Find the last node
		while (temp != NULL && temp->next != NULL)
		{
			temp = temp->next;
		}
		// Add node at last position
		temp->next = node;
	}
}
// Display linked list element
void display(struct LinkNode *node)
{
	if (node == NULL)
	{
		return;
	}
	struct LinkNode *temp = node;
	// iterating linked list elements
	while (temp != NULL)
	{
		printf(" %d →", temp->data);
		// Visit to next node
		temp = temp->next;
	}
	printf(" NULL\n");
}
//return given value is prime or not
int check_prime(int value)
{
	if (value == 1)
	{
		return 0;
	}
	else
	{
		unsigned int flag = 1;
		for (int i = 2; i <= value / 2; i++)
		{
			// None prime number
			if (value % i == 0)
			{
				flag = 0;
				break;
			}
		}
		return flag;
	}
}
// deleted prime node in linked list
void delete_prime(struct SingleLL *sll)
{
	if (sll->head == NULL)
	{
		printf("\nEmpty linked List");
	}
	else
	{
		struct LinkNode *temp = sll->head, *hold = NULL, *prev = NULL;
		while (temp != NULL)
		{
			if (check_prime(temp->data) == 1)
			{
				//delete node found
				hold = temp;
			}
			else
			{
				prev = temp;
			}
			temp = temp->next;
			if (hold != NULL)
			{
				if (hold == sll->head)
				{
					//when delete head node
					sll->head = temp;
					free(hold);
					hold = NULL;
				}
				else
				{
					if (prev != NULL)
					{
						prev->next = temp;
					}
					free(hold);
					hold = NULL;
				}
			}
		}
	}
}
int main(int argc, char
	const *argv[])
{
	struct SingleLL *sll = newLinkedList();
	// Linked list
	// 7 → 1 → 8 → 2 → 4 → 23 → 37 → NULL
	addNode(sll, 7);
	addNode(sll, 1);
	addNode(sll, 8);
	addNode(sll, 2);
	addNode(sll, 4);
	addNode(sll, 23);
	addNode(sll, 37);

	printf(" Before Delete prime nodes \n");
	display(sll->head);
	delete_prime(sll);
	printf(" After Delete prime nodes \n");
	display(sll->head);
	return 0;
}

Output

 Before Delete prime nodes
 7 → 1 → 8 → 2 → 4 → 23 → 37 → NULL
 After Delete prime nodes
 1 → 8 → 4 → NULL