private void button4_Click(object sender, EventArgs e)
        {
            double [] pci=new double[5];
            string b = "";

            for(int i =0; i<pci.Length; i++)
            {
                double a = income[i] / fam[i];
                pci[i] = a;
            }
            for (int i = 0; i < pci.Length; i++)
            {
                for (int j = 0; j < pci.Length;j++ )
                    if (pci[i]<pci[j])
                    {
                        double temp = pci[j];
                        pci[i] = pci[j];
                        pci[j] = temp;

                    }
            }
            for (int i = 0; i < pci.Length; i++)
            {
                b += pci[i].ToString() + "\n";
            }
            MessageBox.Show(b);
        }