SQL with Manoj

Q27. Program to implement Generic Classes for maintaining Linked List:

Create a Template class that implements a singly-linked list. The linked list class should include following member functions-
push_front( ), push_back( ), push_at_any( ), remove_first( ), remove_last( ) & remove_at _any( ).
There may be a private data member size to keep track of no. of items remaining at any given point of time.

… from College notes (BCA/MCA assignments):

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

template <class T>
class NODE{
	private:
		T elm, key;
		NODE *next;
	public:
		void addNodeBeg(NODE **);
		void addNodeEnd(NODE **);
		void addNodePos(NODE **);
		void deleteNode(NODE **);
		void displayList(NODE *);
	};

template <class T>
void NODE<T> :: addNodeBeg(NODE<T> **node){
	NODE *temp;
	cout<<"\n Enter a Value: ";
	cin>>key;
	if(*node == NULL){	// list is Empty.
		*node = new(NODE);
		(*node)->elm = key;
		(*node)->next = NULL;
		}
	else{				// list is not empty.
		temp = new(NODE);
		temp->elm = key;
		temp->next = *node;
		*node = temp;
		}
	}

template <class T>
void NODE<T> :: addNodeEnd(NODE<T> **node){
	NODE *temp;
	cout<<"\n Enter a Value: ";
	cin>>key;
	if(*node == NULL){	// list is Empty.
		*node = new(NODE);
		(*node)->elm = key;
		(*node)->next = NULL;
		}
	else{				// list is not empty.
		temp = *node;
		while(temp->next != NULL)
			temp = temp->next;
		temp->next = new(NODE);
		temp = temp->next;
		temp->elm = key;
		temp->next = NULL;
		}
	}

template <class T>
void NODE<T> :: addNodePos(NODE<T> **node){
	NODE *temp, *ntemp;
	int pos, i=1;
	cout<<"\n Enter a Position No.: ";
	cin>>pos;
	cout<<"\n Enter a Key: ";
	cin>>key;
	if(*node == NULL){	// list is Empty.
		cout<<"\n List is Empty.";
		return ;
		}
	temp = *node;
	while(1){
		if( (temp->next == NULL) || (i == pos) )
			break;
		temp = temp->next;
		i++;
		}
	ntemp = new(NODE);
	ntemp->elm = key;
	ntemp->next = temp->next;
	temp->next = ntemp;
	}

template <class T>
void NODE<T> :: deleteNode(NODE<T> **node){
	NODE *temp, *prev;
	int i=0;
	cout<<"\n Enter an Element of List to Delete: ";
	cin>>key;
	temp = *node;
	prev = temp;
	while(1){
		if(*node == NULL){	// list is Empty.
			cout<<"\n List is Empty.";
			return;
			}
		else if(temp->elm == key){	// Element Found.
			if(i == 0){	// if Element is First Node.
				(*node) = (*node)->next;
				cout<<"\n First Node Deleted.";
				return;
				}
			else
				break;
			}
		else if(temp->next == NULL){
			cout<<"\n Element not Found.";
			return;
			}
		i++;
		prev = temp;
		temp = temp->next;
		}
	prev->next = temp->next;
	cout<<"\n Element Deleted.";
	}


template <class T>
void NODE<T> :: displayList(NODE<T> *node){
	int i=1;
	cout<<"\n\t List: ";
	if(node == NULL)
		cout<<" List is Empty.";
	while(node != NULL){
		cout<<"\t"<<node->elm;
		node = node->next;
		i++;
		}
	}

int _menu(){
	int _ch;
	cout<<"\n List Type:- \n";
	cout<<"\n 1 -> Integer.";
	cout<<"\n 2 -> Float.";
	cout<<"\n 3 -> Character.";
	cout<<"\n Enter your choice: ";
	cin>>_ch;
	return (_ch);
	}

void main(){
	int ch1, ch2;

	NODE<int> int_list;
	NODE<float> float_list;
	NODE<char> char_list;

	NODE<int> *int_start = NULL;
	NODE<float> *float_start = NULL;
	NODE<char> *char_start = NULL;

	while(1){
		clrscr();
		cout<<"\n LINK LIST PROGRAM";
		cout<<"\n ~~~~~~~~~~~~~~~~~ \n";
		cout<<"\n 1 -> Add Node at Begining.";
		cout<<"\n 2 -> Add Node at End.";
		cout<<"\n 3 -> Add Node at Position.";
		cout<<"\n 4 -> Delete Node.";
		cout<<"\n 5 -> Display List.";
		cout<<"\n 6 -> Exit.";
		cout<<"\n Enter your choice: ";
		cin>>ch1;
		switch(ch1){
			case 1:		// Add node at Begining.
				ch2 = _menu();
				switch(ch2){
					case 1:
						cout<<"\n Enter an Integer 
  Value: ";
						int_list.addNodeBeg(&int_start);
						break;
					case 2:
						cout<<"\n Enter a Float Value:”;
					float_list.addNodeBeg(&float_start);
						break;
					case 3:
						cout<<"\n Enter a Character: ";
					char_list.addNodeBeg(&char_start);
						break;
					default:
						cout<<"\n Wrong Entry. No 
  operation Done.";
					}
				break;
			case 2:		// Add node at End.
				ch2 = _menu();
				switch(ch2){
					case 1:
						cout<<"\n Enter an Integer 
  Value: ";
						int_list.addNodeEnd(&int_start);
						break;
					case 2:
						cout<<"\n Enter a Float Value:";
					float_list.addNodeEnd(&float_start);
						break;
					case 3:
						cout<<"\n Enter a Character: ";
					char_list.addNodeEnd(&char_start);
						break;
					default:
						cout<<"\n Wrong Entry. No 
  operation Done.";
					}
				break;
			case 3:		// Add node at Position.
				ch2 = _menu();
				switch(ch2){
					case 1:
						cout<<"\n Enter an Integer 
  Value: ";
						int_list.addNodePos(&int_start);
						break;
					case 2:
						cout<<"\n Enter a Float Value:";
					float_list.addNodePos(&float_start);
						break;
					case 3:
						cout<<"\n Enter a Character: ";
					char_list.addNodePos(&char_start);
						break;
					default:
						cout<<"\n Wrong Entry. No 
  operation Done.";
					}
				break;
			case 4:		// Delete Node.
				ch2 = _menu();
				switch(ch2){
					case 1:
						cout<<"\n Enter an Integer 
  Value: ";
						int_list.deleteNode(&int_start);
						break;
					case 2:
						cout<<"\n Enter a Float Value:";
					float_list.deleteNode(&float_start);
						break;
					case 3:
						cout<<"\n Enter a Character: ";
					char_list.deleteNode(&char_start);
						break;
					default:
						cout<<"\n Wrong Entry. No 
  operation Done.";
					}
				break;
			case 5:		// Display List.
				cout<<"\n\n Integer List: - ";
				int_list.displayList(int_start);
				cout<<"\n\n Float List: - ";
				float_list.displayList(float_start);
				cout<<"\n\n Character List: - ";
				char_list.displayList(char_start);
				break;
			default:
				exit(1);
			}
		getch();
		}
	}

Output:

LINK LIST PROGRAM

1 -> Add Node at Begining.
2 -> Add Node at End.
3 -> Add Node at Position.
4 -> Delete Node.
5 -> Display List.
6 -> Exit.

Enter your choice: 5

Integer List: –
List: 3 90 44 45 23 45

Float List: –
List: 90.449997 23.440001 12.34

Character List: –
List: e r