Lagrange Interpolation by Me

#include <iostream>
#include <cstdlib>

using namespace std;

class Lagrange{
    double **diff_table;
    int n;
    double *x, *y;
    double x_unknown;
    double y_at_x_un;
    public:
        Lagrange(int);
        ~Lagrange();
        void input();
        void calcDiffTable();
        void calcY();
        void display();
};

Lagrange::Lagrange(int n){
    Lagrange::n = n;
    x = new double[n];
    y = new double[n];
    diff_table = new double*[n];
    for(int i = 0; i < n; i++){
        diff_table[i] = new double[n];
    }
}

Lagrange::~Lagrange(){
    delete[] x;
    delete[] y;
    for(int i = 0; i < n; i++){
        delete[] diff_table[i];
    }
}

void Lagrange::input(){
    for(int i = 0; i < n; i++){
        cout << "x[" << i << "] = ";
        cin >> x[i];
        cout << "y[" << i << "] = ";
        cin >> y[i];
    }
    cout << "Enter unknown x: ";
    cin >> x_unknown;
}

void Lagrange::calcDiffTable(){
    // Setting the diagonals
    for(int i = 0; i < n; i++){
        diff_table[i][i] = x_unknown - x[i];
    }
    // Setting rest of the elements
    for(int i = 0; i < n; i++){
        for(int j = 0; j < n; j++){
            if(i != j){
                diff_table[i][j] = x[i] - x[j];
            }
        }
    }
}

void Lagrange::calcY(){
    double l_i;
    y_at_x_un = 0;
    double numerator;
    double denominator;
    for(int i = 0; i < n; i++){
        numerator = 1;
        denominator = 1;
        for(int j = 0; j < n; j++){
            if(i != j){
                numerator = numerator * diff_table[j][j];
                denominator = denominator * diff_table[i][j];
            }
        }
        l_i = numerator / denominator;
        y_at_x_un += (l_i * y[i]);
    }
}

void Lagrange::display(){
    calcDiffTable();
    cout << "\nElements in the Lagranges Difference Table" << endl;
    for(int i = 0; i < n; i++){
        for(int j = 0; j < n; j++){
            cout << diff_table[i][j] << "\t";
        }
        cout << endl;
    }
    cout << endl;
    calcY();
    cout << "Unknown y-value = " << y_at_x_un << endl;
}

int main() {
    system("cls");
    cout << "Enter the number of points: ";
    int n;
    cin >> n;
    Lagrange L(n);
    L.input();
    L.display();
    return 0;
}