16.19

#include "stdafx.h"
#include <iostream>
#include <fstream>

using namespace std;

struct node
{
	int info;
	node *next;
};

void create_listFile(node *&head, ifstream &f)
{

	head = NULL;
	int info = 0;
	while (f >> info)
	{
		node *q = new node;
		q->info=info;
		q->next = head;
		head = q;
	}
}

bool blank(node * head)
{
	return head == NULL;
}

void show_list(node* head)
{
	if (blank(head))
		cout << "Пусто" << endl;
	else
	{
		node* q = head;
		while (q!=NULL)
		{
			cout << q->info << ' ';
			q = q->next;
		}
		cout << endl;
	}
}

void deletFirstEl(node *&head)//A
{
	node *p = head;
	head = head->next;
	p->next = NULL;
	delete p;
}

void deletSecondEl(node *&head)//Б
{
	node *q = head;
	node *p = new node;
	if (blank(head))
		cout << "Пусто" << endl;
	else
	{
		if (head->next == NULL)
			cout << "Короткий список" << endl;
		else
		{
			p = q->next;
			q->next = q->next->next;
			show_list(head);
		}

	}
}

void B(node *&head, int x)//B
{
	node *q = head;
	node *p = new node;
	if (blank(head))
		cout << "Пусто" << endl;
	else
	{
		while (q != NULL)
		{
			if (q->info == x&& q->next != NULL)
			{
				p = q->next;
				q->next = q->next->next;
			}
			q = q->next;
		}
		show_list(head);
	}
}

void endelemet(node *&head)//Г
{
	node *q = head;
	node *p = new node;
	if (blank(head))
		cout << "Пусто" << endl;
	else
	{
		if (head->next== NULL)
		{
			head = NULL;
			q = q->next;
			delete q;
		}
		else
		{
			while (q->next->next != NULL)
				q = q->next;

			p = q->next;
			q->next = NULL;
			delete p;
		}
		show_list(head);
	}
}

void D(node *&head)
{
	node *q = head;
	node *p = new node;
	if (blank(head))
		cout << "Пусто" << endl;
	else
	{
		if (head->next == NULL)
		{
			if (q->info < 0)
			{
				head = NULL;
				q = q->next;
				delete q;
			}
		}
		else
		{
			if (q->info < 0)
				head = q->next;
			else
			{
				while (q != NULL && q->info > 0)
				{
					p = q;
					q = q->next;
				}
				if (q != NULL && q->info < 0)
				{
					p->next = q->next;
					q->next = NULL;
					delete q;
				}
			}



		}
		show_list(head);
	}
}

void E(node *&head)
{
	node *q = head, *mark = head;
	node *p = new node;
	if (blank(head))
		cout << "Пусто" << endl;
	else
	{
		if (head->next == NULL)//список из одного элемента
		{
			if (q->info < 0)
			{
				head = NULL;
				q = q->next;
				delete q;
			}
		}
		else
		{
			while (q->info < 0)
			{
				head = q->next;
				q = head;
			}
			while (q != NULL)
				{
					if (q->info < 0)
					{
						mark->next = q->next;
						q->next = NULL;
						q=mark->next;
					}
					else
					{
						mark = q;
						q = q->next;
					}
				}
		}
		show_list(head);
	}
}

int main()
{
	setlocale(LC_ALL, "Russian");
	node * head = NULL;
	ifstream in("Text.txt");
	create_listFile(head, in);
	show_list(head);
	//deletFirstEl(head);//A
	//deletSecondEl(head);//Б
	//B(head, 3);//B
	//endelemet(head);//Г
	//D(head);
	E(head);

	system("pause");
	return 0;
}