#include <stdio.h>

#include <stdlib.h>



typedef struct Node {

	int data;

	struct Node *nextadd;

}NODE;



NODE *firstnode = NULL;

NODE *lastnode = NULL;

int cnt = 0;



void add(int num) {

	if (cnt > 9) {

		printf("You can't make more than 10 of them.");

		return;

	}

	NODE *newnode = (NODE *)malloc(sizeof(NODE));

	cnt++;

	newnode->data = num;

	newnode->nextadd = NULL;

	if (firstnode == NULL) {



		firstnode = newnode;

		lastnode = newnode;

	}

	else {

		lastnode->nextadd = newnode;

		lastnode = newnode;

	}

}



void erase(int num) {

	NODE *temp = firstnode->nextadd;

	if (firstnode == NULL) {

		printf("No value.\n");

		return;

	}

	if (firstnode->data == num) {



		firstnode = firstnode->nextadd;

		cnt--;



	}

	else {

		NODE *before = firstnode;

		while (1) {

			if (temp->data == num) {

				NODE *node_free = temp;

				before->nextadd = temp->nextadd;

				free(node_free);

				lastnode = before;

				cnt--;

				break;

			}

			else {

				if (temp->nextadd == NULL) {

					printf("No value.\n");

					break;

				}

				before = before->nextadd;

				temp = temp->nextadd;

			}

		}

	}

	return;

}



void insert(int num, int num1) {

	int i;

	if (firstnode == NULL) {

		printf("No value.\n");

		return;

	}

	NODE *temp = firstnode;

	for (i = 1;temp != NULL;++i) {

		if (temp->data == num) {

			NODE *newnode = (NODE *)malloc(sizeof(NODE));

			newnode->data = num1;

			newnode->nextadd = temp->nextadd;

			temp->nextadd = newnode;

			cnt++;

			break;

		}

		temp = temp->nextadd;

	}



}



void show() {

	int i;

	if (firstnode == NULL) {

		printf("No value.\n");

		return;

	}

	else {

		NODE *temp = firstnode;

		for (i = 1; temp != NULL; ++i) {

			printf("%d value : %d \t", i, temp->data);

			temp = temp->nextadd;

		}

	}

}







int main() {

	int select, i, input_num, input_num1;

	int digit = 8;

	while (1) {

		printf("\n\n0 : exit\n");

		printf("1 : Create Node\n");

		printf("2 : Delete Node\n");

		printf("3 : Insert Node\n");

		printf("4 : View nodes\n");

		printf("Select 0-4 : ");

		check_num(&select, digit);



		if (select == 0) {

			return 0;

		}

		else if (select == 1) {

			printf("Please enter a value: ");

			check_num(&input_num, digit);

			add(input_num);



		}

		else if (select == 2) {

			show();

			printf("\nPlease enter a value to clear : ");

			check_num(&input_num, digit);

			erase(input_num);



		}

		else if (select == 3) {



			printf("\n|----------------------------------------------------------------------------------------------------------|");

			printf("\n  EX) first value:A		second value:B		third value:C				                                           ");

			printf("\n  EX) Please enter a value for the location you want to insert: B					    	                                       ");

			printf("\n  EX) Please enter a value to insert: AA									                                       ");

			printf("\n  EX)first value:A		second value:B		third value:AA 	   fourth value:C                              ");

			printf("\n|----------------------------------------------------------------------------------------------------------|\n\n\n\n");

			show();

			printf("\n\nPlease enter a value for the location you want to insert:");

			check_num(&input_num, digit);

			printf("Please enter a value to insert: ");

			check_num(&input_num1, digit);

			insert(input_num, input_num1);



		}

		else if (select == 4) {

			show();

		}

		else {

			printf("Only numbers between 0 and 4 can be entered.");

		}

	}

}



int check_num(int *result, int form) {



	int i;



	int j = 1;



	int sign = 1;



	int input_size;



	char *str;



	*result = 0;



	str = (char *)malloc(sizeof(char) * form + 2);



	while (1) {



		sign = 1;



		fgets(str, form + 2, stdin);



		for (i = 0; i < form + 1; i++) {



			if (str[i] == '\n') {



				input_size = i;



				break;



			}



		}



		if (str[0] == 10) {



			printf("Enter the number and press Enter. \n Please re-enter : ");



			continue;



		}



		if (i == form + 1) {



			printf("The input range has been exceeded. \n");



			while (getchar() != '\n') {



			}



			printf("Please re-enter : ");



			continue;



		}







		for (i = 0; i < input_size; i++) {



			if (str[i] < 48 || str[i] > 57) {



				if (str[i] != '\n') {



					printf("Only integer greater than 0 can be entered.\n");



					printf("Please re-enter : ");



					sign = 0;



					break;



				}



			}



		}



		if (sign == 0) {



			continue;



		}



		for (i = 0; i < input_size; i++) {



			*result = *result + (str[input_size - i - 1] - 48) * j;



			j = j * 10;



		}



		break;



	}



	free(str);



	return 0;



}