private void button2_Click(object sender, EventArgs e)
        {
            SqlCommand cmd = new SqlCommand("stusignup", con);

            cmd.CommandType = CommandType.StoredProcedure;
            cmd.Parameters.AddWithValue("@USN", textBox1.Text);
            cmd.Parameters.AddWithValue("@Name", textBox2.Text);
            cmd.Parameters.AddWithValue("@Branch", textBox3.Text);
            cmd.Parameters.AddWithValue("@Semester", textBox4.Text);
            cmd.Parameters.AddWithValue("@PhoneNo", textBox5.Text);
            cmd.Parameters.AddWithValue("@Email_id", textBox6.Text);
            cmd.Parameters.AddWithValue("@Password", textBox7.Text);
            con.Open();
            try
            {
                cmd.ExecuteNonQuery();
                MessageBox.Show("Sign Up Successful");
            }
            catch (Exception ex)
            {
                MessageBox.Show("INVALID" + ex);
            }
            con.Close();
            introduction obj1 = new introduction();

            this.Hide();
            obj1.Show();
        }
        private void button1_Click(object sender, EventArgs e)
        {
            String Uname = getUsername(), Upass = getPassword(), name, pass;

            name = textBox1.Text;
            pass = textBox2.Text;

            try
            {
                if (name.Equals(Uname) && pass.Equals(Upass))
                {
                    //login
                    label3.Hide();
                    MessageBox.Show("Login success");
                    introduction obj = new introduction();
                    this.Hide();
                    obj.Show();
                }
                else
                {
                    //dont login
                    label3.Show();
                }
            }
            catch (Exception es)
            {
                MessageBox.Show("invalid credentials" + es);
            }
        }