C++ Program code for Lagrange Interpolation

// program for lagrange interpolation

#include <iostream>

using namespace std;

class lagrange
{
public:
    lagrange()
    {
        p = 0;
    }
    void askF();
    void findL();
    void askX();
    void findP();

    void askN()
    {
        cout << "Enter number of values: ";
        cin >> n;
    }
    void askXX()
    {
        cout << "Enter the value of X to find y: ";
        cin >> xx;
    }

private:
    double Li[10],x[10],xx,Fi[10],p;
    int n;
};

void lagrange::findL()
{
        for(int i = 0; i < n; i ++ )
        {
            Li[i] = 1;
            for(int j = 0; j<n;j++)
            {

                if(j!=i)
                {
                    Li[i] *= (xx-x[j])/(x[i]-x[j]);
                }
            }
        }
        cout << endl << endl;
        for(int i = 0;i<n;i++)
        {
            cout <<"Li[" <<i <<"] : "<<Li[i] << endl;
        }
}

void lagrange::askX()
{
    cout << "ENter given Xs :" << endl;
    for (int i = 0; i<n ;i++)
    {
        cout << "ENter x[" << i << "]: " ;
        cin >> x[i];
    }
}

void lagrange::askF()
{
    cout << "ENter F :" << endl;
    for (int i = 0; i<n ;i++)
    {
        cout << "ENter F[" << i << "]: " ;

        cin >> Fi[i];
    }
}

void lagrange::findP()
{
    for(int i = 0;i<n;i++)
    {
        p += Fi[i]*Li[i];
    }
    cout <<endl<<"The Value of P"<< n-1 << "(" << xx << "): "<< p ;
}

int main()
{
    lagrange l1;
    l1.askN();
    l1.askXX();
    l1.askX();
    l1.askF();
    l1.findL();
    l1.findP();

    return 0;
}