Question

C++ Create a program that finds the dot product of two vectors.

I'm currently trying to display the dot product by calling the dotProduct member function however I am confused as to how to do this. What would be the proper way to display the dot product? I don't believe my dotProduct member function is set up correctly to access the proper data. Feel free to modify the dotProduct member function to allow for it to work with the other member functions. Any help would be much appreciated!

#include <iostream>
#include <vector>
#include <ctime>
#include <iomanip>
using namespace std;
class list
{
    public:
        list();
        void input(int s);
        void output();
        double dotProduct(vector <double> a, vector <double> b);
    private:
        vector <int> v;
};
list :: list() : v()
{
}
void list :: input(int s)
{
    int t;
    for(int i = 1; i <= s; i++)
    {
        t = rand() % 10;
        v.push_back(t);
    }
}
void list :: output()
{
    for(unsigned int i = 0; i < v.size(); i++)
        cout << v[i] << " ";
    cout << endl;
}
double list :: dotProduct(vector <double> a, vector <double> b)
{
    double product = 0;
    if(a.size() != b.size())
    {
        cout << "Vectors are not the same size\n";
    }
    for (unsigned int i = 0; i < a.size(); i++)
    {
        product = product + a[i] * b[i];
    }

    return product;

}
int main()
{
    list L1, L2,ob1;
    int s;
    cout << "Enter the size of list 1: \n";
    cin >> s;
    L1.input(s);
    cout << "\nEnter the size of list 2: \n";
    cin >> s;
    L2.input(s);
    cout << "\nVector 1: ";
    L1.output();
    cout << endl;
    cout << "Vector 2: ";
    L2.output();
    cout << endl;

    cout << "The dot product is: ";
    //code here to display the dot product of the two vectors
    cout << endl;   

    return 0;

}

Answer 1

If you have any doubts, please give me comment...

#include <iostream>

#include <vector>

#include <ctime>

#include <iomanip>

#include <cstdlib>

using namespace std;

class list

{

public:

    list();

    void input(int s);

    void output();

    double dotProduct(const list &a);

private:

    vector<int> v;

};

list ::list() : v()

{

}

void list ::input(int s)

{

    int t;

    for (int i = 1; i <= s; i++)

    {

        t = rand() % 10;

        v.push_back(t);

    }

}

void list ::output()

{

    for (unsigned int i = 0; i < v.size(); i++)

        cout << v[i] << " ";

    cout << endl;

}

double list ::dotProduct(const list &a)

{

    double product = 0;

    if (v.size() != a.v.size())

    {

        cout << "Vectors are not the same size\n";

    }

    for (unsigned int i = 0; i < v.size(); i++)

    {

        product = product + v[i] * a.v[i];

    }

    return product;

}

int main()

{

    list L1, L2, ob1;

    int s;

    cout << "Enter the size of list 1: \n";

    cin >> s;

    L1.input(s);

    cout << "\nEnter the size of list 2: \n";

    cin >> s;

    L2.input(s);

    cout << "\nVector 1: ";

    L1.output();

    cout << endl;

    cout << "Vector 2: ";

    L2.output();

    cout << endl;

    cout << "The dot product is: ";

    double result = L1.dotProduct(L2);

    cout<<result<<endl;

    cout << endl;

    return 0;

}