Question

Using the following definition (List.h file) for a list, implement the member functions (methods) for the List class and store the implementation in a List.cpp file. Use a doubly linked list to implement the list. Write the client code (the main method and other non-class methods) and put in file driver.cpp.

file: List.h typedef int ElementType; class node{ ​ElementType data; ​node * next; node* prev; };

class List {

public: List(); //Create an empty list

bool Empty(); // return true if the list is empty, otherwise return false

void InsertAtEnd(ElementType x); //insert a value x on the end of the list

void Delete(ElementType x); //if value x is in the list, remove x

void Display(); //Display the data values in the list in the order inserted​

int Sum(); // Compute and return the sum of the values in the list

int Average(); // Compute and return the average of the values in the list

private:

node * first;

//think of other data members that can potentially make your life easier:

//node* last?

//count ?

}

Your client code should be menu driven using the following menu options:

1. Insert
2. Delete
3. Display
4. Sum
5. Average
6. Exit

Option 1: Insert a new value on the end of the list.

Option 2: Delete a number specified by the user from the list, if the number is in the list.

Option 3: Displayed in the list of numbers.

Option 4: Compute and return the sum of the values in the list. If the list is empty return 0.

Option 5: Compute and return the average of the values in the list. If the list is empty return 0.

Option 6: Exits the program.

Answer 1

List.h

//file: List.h
typedef int ElementType;
const int MAX = 100;
class List
{
public:
List(); //Create an empty list
bool Empty(); // return true if the list is empty, otherwise return false
void InsertAtEnd(ElementType x); //insert a value x on the end of the list
void Delete(ElementType x); //if value x is in the list, remove x
void Display(); //Display the data values in the list in the order inserted
int Sum(); // Compute and return the sum of the values in the list
int Average(); // Compute and return the average of the values in the list
  
private:
int N; //number of values in list
ElementType listArray[MAX]; //the array to hold the list values
};

main.cpp

#include <iostream>
#include "List.h"

int main() {
  
List myList;
  
std::cout<<"Main Menu \n 1. Insert \n 2. Delete \n 3.Display \n 4. Sum \n 5. Average \n 6. Exit \n";
std::cout<<"Enter the number of the menu item you would like to select \n";
  
int menuSelection;
  
std::cin>>menuSelection;
  
ElementType inValue;
  
  
if (menuSelection == 1) {
std::cout<<"\nEnter the value you would like to add: \n";
  
std::cin>>inValue;
myList.InsertAtEnd(inValue);
}else if (menuSelection == 2){
std::cout<<"\nEnter the value you would like to delete: \n";
  
ElementType delValue;
std::cin>>delValue;
  
myList.Delete(delValue);
}else if (menuSelection == 3){
myList.Display();
}else if (menuSelection == 4){
myList.Sum();
}else if (menuSelection == 5){
myList.Average();
}else{
exit(0);
}
  
}

List.cpp

#include <iostream>
#include "List.h"

List::List(){
ElementType listArray[MAX];
N = 0;
}

bool List::Empty(){
if (N == 0){
return true;
}else{
return false;
}
}

void List::InsertAtEnd(ElementType x){
listArray[N] = x;
}

void List::Delete(ElementType x){
//TODO create delete method
//if value x is in the list, remove x
for(int i = 0; i < MAX; i++){
if(listArray[i] == x){
listArray[i] = 0;
N--;
}
}
}

void List::Display(){
for (int i = 0; i < MAX; i++) {
std::string s = std::to_string(listArray[i]);
std::cout<<"\n" + s;
}
}

int List::Sum(){
int sum = 0;
for(int i = 0; i < MAX; i++){
sum += listArray[i];
}
return sum;
}

int List::Average(){
int sum = 0;
for(int i = 0; i < MAX; i++){
sum += listArray[i];
}
return sum/N;
}