Array in Classes

Question

I'm still new to classes so here what i have done so far. In this program I have to prompt the user to input how many products and the prices and i have to display back again like this :

No     Product Code    Price
1         101          4.50

and calculate the average price.

my class have to hold up to 100 objects which I'm still not sure how o implement. Hope anyone can help me with this.

#include <iostream>

using namespace std;


class Product{
private :
    int code;
    double price;

public :
    Product ();
    void setCode(int);
    void setPrice(double);

    int getCode();
    double getPrice();
};

Product :: Product()
{
    code = 0;
    price = 0;
}

void Product :: setCode(int c)
{
    code = c;
}

void Product :: setPrice(double p)
{
    price = p;
}

int Product :: getCode()
{
    return code;
}

double Product :: getPrice()
{
    return price;
}

int main(){

    const int size = 100;
    Product m[size];
    int procode;
    double proprice;
    int num;
    double sum= 0;

    cout << "How many products to enter? ";
    cin >> num;

    cout << endl;

    for(int i=0; i<num ;i++)
    {
        cout << "Enter the information of product #"<< (i+1)<<endl;

        int code;
        cout << "\tProduct Code: ";
        cin >> code;
        m[i].setCode( code );

        double price;
        cout << "\tPrice: ";
        cin >> price;
        m[i].setPrice( price );

        sum = sum + price;
    }

    ///output??
    cout <<"No"<<"   "<<"Product Code"<<"   "<<"Price" <<endl;


    cout<<"   "<<m[i].getCode()<<"   "<<m[i].getPrice()<<endl;

    cout<<"Average: " << sum/num << endl;


    return 0;

}

Answer 1

Did you mean dynamic allocation? If you want to have variable amount of Products specified by user, you must create the array dynamically after you know num. For example:

int main() {

    Product * m;
    int num;

    cout << "How many products to enter? ";
    cin >> num;
    cout << endl;

    m = new Product[num];

    for (int i=0; i<num; i++) {
        // something with the array
    }

    delete [] m;

    return 0;

}

Answer 2

Function main can be written the following way

int main()
{
    const size_t MAX_ITEMS = 100;
    Product m[MAX_ITEMS];
    size_t num;

    cout << "How many products to enter? ";
    cin  >> num;

    if ( MAX_ITEMS < num ) num = MAX_ITEMS;

    for ( size_t i = 0; i < num; i++ )
    {
        cout << "\nEnter the information of product #" << (i+1) << endl;

        int code;
        cout << "\tProduct Code: ";
        cin >> code;
        m[i].setCode( code );

        double price;
        cout < "\tPrice: ";
        cin >> price;
        m[i].setPrice( price );
    }

    // here can be the code for output data

    return 0;
}

Answer 3

for(int i=0; i<num ;i++)
    {
        cout << "Enter the information of product #"<< (i+1)<<endl;
        cout << "Product Code:";
        cin >> procode;
        m[i].setCode(procode);
        cout < "\nPrice:";
        cin >> proprice;
        m[i].setPrice(proprice);
    }

This will set required number of objects.

Access as

  cout<<m[index].getCode()<<m[index].getPrice();