kalkulator

using System;
using System.Windows.Forms;

namespace MojaAplikacjaFormsowa
{
    public partial class Form1 : Form
    {
        private decimal? zmienna = null;

        public Form1() => InitializeComponent();

        private void button1_Click(object sender, EventArgs e) => WindowState = FormWindowState.Minimized;

        private void button19_Click(object sender, EventArgs e) => WindowState = FormWindowState.Maximized;

        private void button10_Click(object sender, EventArgs e)
        {

        }

        private void button12_Click(object sender, EventArgs e)
        {

        }

        private void button11_Click(object sender, EventArgs e)
        {

        }

        private void button17_Click(object sender, EventArgs e)
        {

        }

        private void button15_Click(object sender, EventArgs e)
        {

        }

        private void button15_Click_1(object sender, EventArgs e)
        {
            if (textBox1.Text.IndexOf(",") == -1)
            {
                textBox1.Text += ",";
            }
        }

        private void button17_Click_1(object sender, EventArgs e) => textBox1.Text += button17.Text;

        private void textBox1_TextChanged(object sender, EventArgs e)
        {

        }

        private void button16_Click(object sender, EventArgs e) => textBox1.Text += button16.Text;

        private void button14_Click(object sender, EventArgs e) => textBox1.Text += button14.Text;

        private void button10_Click_1(object sender, EventArgs e) => textBox1.Text += button10.Text;

        private void button11_Click_1(object sender, EventArgs e) => textBox1.Text += button11.Text;

        private void button2_Click(object sender, EventArgs e) => textBox1.Text += button2.Text;

        private void button3_Click(object sender, EventArgs e) => textBox1.Text += button3.Text;

        private void button4_Click(object sender, EventArgs e) => textBox1.Text += button4.Text;

        private void button13_Click(object sender, EventArgs e) => textBox1.Text += button13.Text;

        private void button12_Click_1(object sender, EventArgs e) => textBox1.Text += button12.Text;

        private void button18_Click(object sender, EventArgs e) => textBox1.Text = null;





        private void wykonajDzialanie(decimal wartosc, string dzialanie)
        {
            switch (dzialanie)
            {
                case "+":
                    zmienna += decimal.Parse(textBox1.Text) + wartosc;
                    break;
                case "-":
                    zmienna -= decimal.Parse(textBox1.Text) + wartosc;
                    break;
                case "x":
                    zmienna *= decimal.Parse(textBox1.Text) + wartosc;
                    break;
                case "%":
                    zmienna /= decimal.Parse(textBox1.Text) + wartosc;
                    break;
                case "=":
                    textBox1.Text = zmienna.ToString();
                    break;
            }
        }

        private void button5_Click(object sender, EventArgs e)
        {
            wykonajDzialanie("%");
            textBox1.Text = "";
        }

        private void button6_Click(object sender, EventArgs e)
        {
            wykonajDzialanie("x");
            textBox1.Text = "";
        }

        private void button8_Click(object sender, EventArgs e)
        {
            wykonajDzialanie("+");
            textBox1.Text = "";
        }

        private void button9_Click(object sender, EventArgs e)
        {
            wykonajDzialanie("=");
            textBox1.Text = "";
        }

        private void button7_Click(object sender, EventArgs e)
        {
            wykonajDzialanie("-");
            textBox1.Text = "";
        }
    }
}