gistfile1.c

#include <stdio.h>
#include <stdlib.h>
#include <conio.h>

struct list{
		int num;
		struct list * next;
	};

	struct list * begin = NULL, * end = NULL, * p, * tmp;
	int choice, el, number = 0, position, i;


void add() {
	printf("\nEnter the new element: ");
		scanf("%d", &el);

	if (begin == NULL) {
		p = (list *)malloc(sizeof(list));
		begin = p;
		end = p;
		p->num = el;
		p->next = NULL;
		printf("\nReady.\n");
		number++;
		return;
	}
	
	printf("\nPosition of the element in the list of %d: ", number);
	scanf("%d", &position);
	if (position <= number) {
		p = begin;
		for (i = 0; i < position - 2; i++){
			p = p->next;
		}
		tmp = p->next;
		p->next = (list *)malloc(sizeof(list));
		p->next->num = el;
		p->next->next = tmp;
	}
	else {
		printf("\nAdding to the end of the list.");
		end->next = (list *)malloc(sizeof(list));
		end = end->next;
		end->num = el;
		end->next = NULL;
	}
	printf("\nReady.\n");
	number++;
	return;
}



void del() {
	
	if (begin == NULL) {
		printf ("\nList is empty.\n");
		return;
	}
		
	printf("\nPosition of the element to delete in the list of %d: ", number);
	scanf("%d", &position);
	if (position <= number) {
		if(number = 1){
			p = begin;
			free(p);
			begin = NULL;
			end = NULL;
			printf("\nReady.\n");
			number--;
			return;
		}
		
		p = begin;
		for (i = 0; i < position - 1; i++) {
			p = p->next;
		}
		tmp = p->next->next;
		free(p->next);
		p->next = tmp;
		if(position = 1) begin = p->next;
	}
	else {
		printf("\nDeleting the last element.");
		for(p = begin; p->next = end; p = p->next);
		free(p->next);
		p->next = NULL;
		end = p;
	}
	printf("\nReady.\n");
	number--;
	return;

}

void print() {
	p = begin;
	if (p == NULL) {
		printf ("\nList is empty.\n");
		return;
	}
	while (p != NULL) {
		printf(" %d ", p->num);
		p = p->next;
	}
	printf("\n");
}


int main() {

	printf ("0 - print, 1 - add, 2 - delete.\n");

	while(1) {
		scanf("%d", &choice);
		switch (choice) {
 			case 0 : {
				 print();
			} break;
			case 1 : {
				add();
			} break;
			case 2 : {
				del();
			} break;
		}

	}
	return 0;
}