Question

Suppose that class OrderList has a private attribute double cost[100] which hold the cost of all ordered items, and a private attributes int num_of_items which hold the number of items ordered. For example, if num_of_items is 5, then cost[0], cost[1], ..., cost[4] hold the cost of these 5 items. Implement the member function named total_cost which returns the total cost of this OrderList.

Answer 1

In the c++ code below we have a class called OrderList that has two data members- cost[] that stores cost of each item and n_of_items that stores number of items.

And then we have a member function total_cost() that calculates and returns the total cost of the items.

First, it asks user to enter the number of items and then runs a for loop that number of times to gat the cost of each item from the user. Simultaneously, it sums up the costs and finally returns the sum.

CODE:

#include<iostream>

using namespace std;

class OrderList

{

private:

double cost[100];

int num_of_items;

public:

double total_cost() //defining the member function

{

int i;

double sum = 0; //to get the total cost

cout<<"Enter the number of items: ";

cin>>num_of_items;

cout<<"Now enter cost of each item:\n";

for(i=0;i<num_of_items;i++)

{

cin>>cost[i];

sum +=cost[i]; //adding each cost to the sum

}

return sum; //returning the sum

}

};

int main()

{

OrderList o; //creatiing object of the class

double sum;

sum = o.total_cost(); //calling the member function

cout<<"The total cost is: "<<sum;

return 0;

}

OUTPUT: