TwoWayLinkedList.cpp

/**
* Developer: Minhas Kamal (BSSE-0509, IIT, DU)
* Date: 13.Sep.2013
**/

#include<iostream>
#include<list>

using namespace std;

list<int> creatList();              //creates the list
void traversing(list<int> myList, int choice);  //prints all the integers in the list
int searching(list<int> myList, int searchingElement);      //searches for selected element
list<int> deleting(list<int> myList, int deletingElement, int selection);   //deleting selected element
list<int> insertingAtBeginning(list<int> myList, int insertingElement);   //inserting at beginning
list<int> insertingAtEnd(list<int> myList, int insertingElement);   //inserting at end
list<int> inserting(list<int> myList, int destinationElement, int insertingElement, int a); //inserts certain element in definite place
list<int> destroy(list<int> myList);    //destroying the list


int main()
{
    list<int> myList;
    myList = creatList();

    while(true)
    {
        int selection;  //user action
        cout << "\n##What do you want to do? \npress- 1 for traversing\n";  //user prompt
        cout << "       2 for searching\n       3 for deleting\n       4 for inserting\n";
        cout << "       5 for exit\nSelection: ";
        cin >> selection;


        if(selection==1){
            int choice;
            cout << "How do you want to traverse?\npress- 1 for traversing first to last";
            cout << "\n       2 for traversing last to first\nSelection: ";
            cin >> choice;
            traversing(myList, choice);
        }

        else if(selection==2)
        {
            int searchingElement;   //the element to be searched
            cout << "Enter the element you want to search for: ";
            cin >> searchingElement;

            cout << "\n";
            cout << "* " << searchingElement << " is found " << searching(myList, searchingElement) << " times.\n";
        }

        else if(selection==3)
        {
            int deletingElement;    //the element to be deleted
            cout << "Enter the element: ";
            cin >> deletingElement;

            int sel=0;    //determines the correct element
            cout << "Press 1 for deleting " << deletingElement;
            cout << "\n      2 for deleting the element after " << deletingElement;
            cout << "\n      3 for deleting the element before " << deletingElement << "\nSelection- ";
            cin >> sel;

            myList = deleting(myList, deletingElement, sel);
        }

        else if(selection==4)
        {
            int insertingElement, destinationElement, sel;    //the element to be deleted
            cout << "Enter the element: ";
            cin >> insertingElement;
            cout << "Where do you want to insert? \nPress 1 for beginning";
            cout << "\n      2 for end\n      3 for chosing destination\nSelection: ";
            cin >> sel;

            if(sel==1) myList = insertingAtBeginning(myList, insertingElement);
            else if(sel==2) myList = insertingAtEnd(myList, insertingElement);
            else{
                cout << "Enter the destination element: ";
                cin >> destinationElement;

                int a=0;    //determines the correct element
                cout << "Press 1 for inserting after " << destinationElement;
                cout << "\n      2 for inserting before " << destinationElement << "\nSelection- ";
                cin >> a;

                myList = inserting(myList, destinationElement, insertingElement, a);
            }
        }

        else if(selection==5) break;

        else cout << "#Invalid input!\n";
    }
    myList = destroy(myList);
}


list<int> creatList()   //creates the list
{
    list<int> myList;   //declaring the list
    int intNumber,  //the number of integers
        input;      //the input that the user gives

    cin >> intNumber;
    for(int i=0; i<intNumber; i++)
	{
		cin >> input;
		myList.push_back(input);
	}
    return myList;
}

void traversing(list<int> myList, int choice) //prints the List
{
    list<int>:: iterator it;    //declaring a iterator

    cout << endl;
    if(choice==1)
        for(it=myList.begin(); it!=myList.end(); it++)
            cout << *it << "  ";
    else
        for(it=myList.end(); it!=myList.begin(); ){
            it--;
            cout << *it << "  ";
        }
	cout << endl << endl ;
}

int searching(list<int> myList, int searchingElement)
{
    int found=0;  //number of the searching element
    list<int>:: iterator it, //declaring iterator
                         old=myList.begin(); //this will store old position

	for(it=myList.begin(); it!=myList.end(); it++){
		if(searchingElement==*it){
            it++;
            if(old!=myList.begin() && it!=myList.end()){
                cout << "*between " << *old << " and " << *it << endl;
            }
            else if(old==myList.begin()) cout << "*at beginning\n";
            else cout << "*at end\n";
            it--;
            found++;
		}
        old=it;
	}
    return found;
}

list<int> deleting(list<int> myList, int deletingElement, int choice)
{
    int flag=1;
    if(choice==1) myList.remove(deletingElement);
    else if(choice==2) {
        list<int>:: iterator it;    //declaring iterator
        flag=0;

        for(it=myList.begin(); it!=myList.end(); it++){
            if(deletingElement==*it){
                it++;
                it=myList.erase(it);
                flag=1;
                if(it==myList.end()) break;
            }
        }
    }
    else {
        list<int>:: iterator it;    //declaring iterator
        flag=0;

        for(it=myList.begin(); it!=myList.end(); it++){
            if(deletingElement==*it){
                it--;
                it=myList.erase(it);
                flag=1;
                if(it==myList.end()) break;
            }
        }
    }

    if(flag) cout << "\n* Deleted!\n";
    return myList;
}

list<int> insertingAtBeginning(list<int> myList, int insertingElement)
{
    myList.insert(myList.begin(), insertingElement);
    cout << "\n* Inserted!!\n";
    return myList;
}

list<int> insertingAtEnd(list<int> myList, int insertingElement)
{
    myList.insert(myList.end(), insertingElement);
    cout << "\n* Inserted!!\n";
    return myList;
}

list<int> inserting(list<int> myList, int destinationElement, int insertingElement, int a)
{
    int flag=0;
    list<int>:: iterator it;    //declaring iterator

    for(it=myList.begin(); it!=myList.end(); it++){
        if(destinationElement==*it) {
            flag=1;
            break;
        }
    }
    if(a==1) it++;
    myList.insert(it, insertingElement);

    if(flag) cout << "\n* Inserted!!\n";
    else cout << "Destination not found.\n";

    return myList;
}

list<int> destroy(list<int> myList)
{
    myList.clear();
    return myList;
}