ilepkt = 20;
    blad = zeros(1, ilepkt);
    blad2 = zeros(1, ilepkt);
    clc;
    x = [0, 1, 2, 3];
    y = [1; -2; 1; 0];
    for i = 5:ilepkt
        x(i) = i;
        y(i) = randi(10);
        W = vander(x)\y;
        L = lagrange(x, y);
        newy = polyval(W, x);
        newnewy = polyval(L, x);
        blad(i) = mean(abs(newy - y'));
        blad2(i) = mean(abs(newnewy - y'));
        disp(['', num2str(i), '.  V = ', num2str(blad(i)), '  L = ', num2str(blad2(i))]);
    end
    figure(1);
    plot(x, blad, '*');
    hold;
    plot(x, blad2, 'g*');
    hold;
    
    figure(2);
    plot(x, y, 'g*');
    hold;
    plot(x, newnewy, x, newy, 'r');
    hold;