include stdio include conio include windows include locale struct lett

#include <stdio.h>
#include <conio.h>
#include <windows.h>
#include <locale>

struct letter
{
	char chr;
	letter *ltr;
};

void add(letter **h, letter **t, char lt)
{
	letter *n;
	if (!(n = (letter *)calloc(1, sizeof(letter))))
	{
		puts("error!");
		return;
	}
	if (!*t) 
	{	
		*t=n;
		*h=n;
	}
	(*t)->ltr = n;
	n->chr = lt;
	n->ltr = NULL;
	*t = n;
	
}

void see(letter *h)
{
	letter *n = h;
	while (n)
	{
		if (!n)
		{
			puts("error");
			return;
		}
		printf("%c", n->chr);
		n = n->ltr;
	}
}

void del(letter **h, letter **t)
{
	letter *current, *n, *n2 = *h;
	for (n = *h; n->ltr->ltr; n = n->ltr)
	{
		current = n->ltr;
		while (current)
		{	
			if (n -> chr == current -> chr) 
			{
				n2->ltr = current->ltr->ltr;
				free(current);
				current = n2->ltr;
			}
			else
			{
				n2 = current;
				current = current->ltr;
			}
		}

	}
}

void main()
{
	system("cls");
	setlocale(LC_ALL, "rus");

	letter *h=NULL, *t=NULL;
	char *slovo;
	if (!(slovo = (char *)calloc(255, sizeof(char))))
		return;

	printf("Введите слово: ");
	gets(slovo);

	for (int i =0; *(slovo + i); i++)
		add(&h, &t, *(slovo + i));

	see(h);
	del(&h, &t);
	printf("\n\n");
	see(h);
	getch();
}