namespace Calculator

{

    public partial class Form1 : Form

    {

        int value1;

        int value2;

        string operation;

        int result;

​

        public Form1()

        {

            InitializeComponent();

        }

​

        private void button2_Click(object sender, EventArgs e)

        {

            textBox1.Text = textBox1.Text + "2";

        }

​

        private void button1_Click(object sender, EventArgs e)

        {

            textBox1.Text = textBox1.Text + "1";

        }

​

        private void button3_Click(object sender, EventArgs e)

        {

            textBox1.Text = textBox1.Text + "3";

        }

​

        private void button6_Click(object sender, EventArgs e)

        {

            textBox1.Text = textBox1.Text + "4";

        }

​

        private void button7_Click(object sender, EventArgs e)

        {

            textBox1.Text = textBox1.Text + "5";

        }

​

        private void button8_Click(object sender, EventArgs e)

        {

            textBox1.Text = textBox1.Text + "6";

        }

​

        private void button11_Click(object sender, EventArgs e)

        {

            textBox1.Text = textBox1.Text + "7";

        }

​

        private void button12_Click(object sender, EventArgs e)

        {

            textBox1.Text = textBox1.Text + "8";

        }

​

        private void button10_Click(object sender, EventArgs e)

        {

            textBox1.Text = textBox1.Text + "9";

        }

​

        private void button13_Click(object sender, EventArgs e)

        {

            textBox1.Text = textBox1.Text + "0";

        }

​

        private void button4_Click(object sender, EventArgs e)

        {

            operation = "+";

            value1 = int.Parse(textBox1.Text);

            textBox1.Clear();

        }

​

        private void button9_Click(object sender, EventArgs e)

        {

            operation = "-";

            value1 = int.Parse(textBox1.Text);

            textBox1.Clear();

        }

​

        private void button5_Click(object sender, EventArgs e)

        {

            operation = "*";

            value1 = int.Parse(textBox1.Text);

            textBox1.Clear();

        }

​

        private void button16_Click(object sender, EventArgs e)

        {

            operation = "/";

            value1 = int.Parse(textBox1.Text);

            textBox1.Clear();

        }

​

        private void button15_Click(object sender, EventArgs e)

        {

            value2 = int.Parse(textBox1.Text);

​

            if (operation.Equals("+"))

                result = value1 + value2;

​

            if (operation.Equals("-"))

                result = value1 - value2;

​

            if (operation.Equals("*"))

                result = value1 * value2;

​

            if (operation.Equals("/"))

                result = value1 / value2;

​

            textBox1.Text = result.ToString();

        }

​

        private void button17_Click(object sender, EventArgs e)

        {

            textBox1.Clear();

            result = 0;

            value1 = 0;

            value2 = 0;

        }

    }

}