Question

1. Create all necessary code to make this main function work. It is not allowed to change the main function.

int main() {        int ListDataSample1[] = { 1, 1, 1 };        int ListDataSample2[] = { 2, 2, 2 };        List<int> List1 = List<int>(ListDataSample2, 3);        List<int> List2 = List<int>(ListDataSample2, 3);               cout << "List1 :" << List1 << endl;        cout << "List2 :" << List2 << endl << endl;        List1 += List2;               cout << "List1 :" << List1 << endl;        cout << "List2 :" << List2 << endl << endl;        system("pause");        return 0; }

Answer 1

Here is the completed code for this problem. Comments are included, go through it, learn how things work and let me know if you have any doubts or if you need anything to change. If you are satisfied with the solution, please rate the answer. Thanks

#include<iostream>

using namespace std;

//templated List class

template<typename T>

class List{

                //array pointer to store data

                T* arr;

                //current number of elements

                int size;

                public:

                //constructor taking an array pointer and size

                List(T* _arr, int _size){

                                //initializing dynamic array

                                arr=new T[_size];

                                //copying size

                                size=_size;

                                //copying all elements from _arr to arr

                                for(int i=0;i<size;i++){

                                               arr[i]=_arr[i];

                                }

                }

                //destructor to deallocate memory occupied by arr

                ~List(){

                                delete[] arr;

                }

                //overloaded << operator (defined outside the class)

                template <typename T2>

                friend ostream& operator << (ostream &out, const List<T2> &list);

               

                //overloaded += operator method

                List& operator +=(const List& other){

                                //creating a new array with enough capacity to store elements of both arrays

                                T* newArr=new T[size+other.size];

                                //copying elements of this array to newarr

                                for(int i=0;i<size;i++){

                                               newArr[i]=arr[i];

                                }

                                //copying elements of other array to newarr

                                for(int i=0;i<other.size;i++){

                                               newArr[i+size]=other.arr[i];

                                }

                                //destroying old array from this object

                                delete[] arr;

                                //replacing with new array

                                arr=newArr;

                                //updating size

                                size=size+other.size;

                                //returning this object

                                return *this;

                }

};

//overloaded << operator to print the contents of a list

template<typename T2>

ostream& operator << (ostream &out, const List<T2> &list){

                //looping and printing all elements of list separated by comma and space

                //since this is a friend function of List class, it can access private elements of

                //list class

                for(int i=0;i<list.size;i++){

                                out<<list.arr[i];

                                if(i!=list.size-1){

                                               out<<", ";

                                }

                }

                return out;

}

//no change is made to main method

int main()

{

    int ListDataSample1[] = { 1, 1, 1 };

    int ListDataSample2[] = { 2, 2, 2 };

    List<int> List1 = List<int>(ListDataSample2, 3);

    List<int> List2 = List<int>(ListDataSample2, 3);

    cout << "List1 :" << List1 << endl;

    cout << "List2 :" << List2 << endl

         << endl;

    List1 += List2;

    cout << "List1 :" << List1 << endl;

    cout << "List2 :" << List2 << endl

         << endl;

    system("pause");

    return 0;

}

/*OUTPUT*/

List1 :2, 2, 2

List2 :2, 2, 2

List1 :2, 2, 2, 2, 2, 2

List2 :2, 2, 2