
        private void button2_Click(object sender, EventArgs e)
        {
            if (textBox1.Text != "")
            {
                int stno = Convert.ToInt32(textBox1.Text);
                output = new FileStream("Student.Rnd", FileMode.Open, FileAccess.Write);
                binaryOutput = new BinaryWriter(output);
                if (stno > 0 && stno < NUMBER_OF_REC)
                {
                    output.Seek((stno - 1) * randomAccessRecord.SIZE, SeekOrigin.Begin);
                    binaryOutput.Write(stno);
                    record.fName = textBox2.Text;
                    record.lName = textBox3.Text;
                    record.Grade = Convert.ToDouble(textBox4.Text);
                    binaryOutput.Write(record.fName);
                    binaryOutput.Write(record.lName);
                    binaryOutput.Write(record.Grade);
                }
                else
                    MessageBox.Show("Invalid stNo");
                output.Close();
                clearTextBox();
            }
            else
                MessageBox.Show("Please enter stNo");

        }

  
