private void button4_Click(object sender, EventArgs e)
        {
            int[] notas = new int[12];
            for (int i = 0; i < 12; i++)
            {
                notas[i] = Convert.ToInt32(formandos[i, 1]);
            }
            label3.Text=  label3.Text + Convert.ToString(GetMax(notas));
            label4.Text = label4.Text + Convert.ToString(GetMin(notas));
            label5.Text = label5.Text + Convert.ToString(GetAvg(notas));

        }
        public static int GetMax(int[] intCollection)
        {
            int max = int.MinValue;
            foreach (int i in intCollection)
            {
                if (i > max)
                {
                    max = i;
                }
            }

            return max;
        }

        public static int GetMin(int[] intCollection)
        {
            int min = intCollection[0];
            foreach (int i in intCollection)
            {
                if (i < min)
                {
                    min = i;
                }
            }

            return min;
        }

        public static int GetAvg(int[] intCollection)
        {
            int avg = 0;
            foreach (int i in intCollection)
            {
                    avg += i;
            }

            return avg/intCollection.Length;
        }