6.2

#include <iostream>

using namespace std;

int main(){
    int n; //
    double xp; //
    double yp=0.0;
    cout<<"n=";
    cin>>n;
    double x[n];
    double y[n];
    for (int l=0;l<n;l++){
        cout<<"x_"<<l<<" || y_"<<l<<endl;
        cin>>x[l]>>y[l];
    }
        for (int l=0;l<n;l++){
        cout<<"x_"<<l<<"="<<x[l]<<" || y_"<<l<<"="<<y[l]<<endl;
    }
    cout<<"approximation point:xp=";
    cin>>xp;
    double P;//
    for (int i = 0;i<n;i++){
        P=1.0;
        for (int k=0;k<n;k++){
            if(i!=k){
                P*=(xp-x[k])/(x[i]-x[k]);
            }
        }
        yp+=P*y[i];
    }
    cout<<"xp="<<xp<<endl;
    cout<<"yp="<<yp<<endl;
    return 0;
}