TheAlgorithms-C-Plus-Plus/data_structure/Linked List.cpp

#include <iostream>
using namespace std;

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

node *start;

void insert(int x)
{
	node *t = start;
	if (start != NULL)
	{
		while (t->next != NULL)
		{
			t = t->next;
		}
		node *n = new node;
		t->next = n;
		n->val = x;
		n->next = NULL;
	}
	else
	{
		node *n = new node;
		n->val = x;
		n->next = NULL;
		start = n;
	}
}

void remove(int x)
{

	if (start == NULL)
	{
		cout << "\nLinked List is empty\n";
		return;
	}
	else if (start->val == x)
	{
		node *temp = start;
		start = start->next;
		delete temp;
		return;
	}

	node *temp = start, *parent = start;

	while (temp != NULL && temp->val != x)
	{
		parent = temp;
		temp = temp->next;
	}

	if (temp == NULL)
	{
		cout << endl
			 << x << " not found in list\n";
		return;
	}

	parent->next = temp->next;
	delete temp;
}

void search(int x)
{
	node *t = start;
	int found = 0;
	while (t != NULL)
	{
		if (t->val == x)
		{
			cout << "\nFound";
			found = 1;
			break;
		}
		t = t->next;
	}
	if (found == 0)
	{
		cout << "\nNot Found";
	}
}

void show()
{
	node *t = start;
	while (t != NULL)
	{
		cout << t->val << "\t";
		t = t->next;
	}
}

void reverse()
{
	node *first = start;
	node *second = first->next;
	while (second != NULL)
	{
		node *tem = second->next;
		second->next = first;
		first = second;
		second = tem;
	}

	start->next = NULL;
	start = first;
}

int main()
{
	int choice, x;
	do
	{
		cout << "\n1. Insert";
		cout << "\n2. Delete";
		cout << "\n3. Search";
		cout << "\n4. Print";
		cout << "\n5. Reverse";
		cout << "\n0. Exit";
		cout << "\n\nEnter you choice : ";
		cin >> choice;
		switch (choice)
		{
		case 1:
			cout << "\nEnter the element to be inserted : ";
			cin >> x;
			insert(x);
			break;
		case 2:
			cout << "\nEnter the element to be removed : ";
			cin >> x;
			remove(x);
			break;
		case 3:
			cout << "\nEnter the element to be searched : ";
			cin >> x;
			search(x);
			break;
		case 4:
			show();
			cout << "\n";
			break;
		case 5:
			cout << "The reversed list: \n";
			reverse();
			show();
			cout << "\n";
			break;
		}
	} while (choice != 0);

	return 0;
}