using System; using System.Text; using System.Windows.Forms; namespace WindowsFormsApplication1 { public partial class Form1 : Form { string oper; string num1, num2 = null; public Form1() { InitializeComponent(); } private void Button1_Click(object sender, EventArgs e) { TextBox1.AppendText("1"); } private void Button2_Click(object sender, EventArgs e) { TextBox1.AppendText("2"); } private void Button3_Click(object sender, EventArgs e) { TextBox1.AppendText("3"); } private void Button4_Click(object sender, EventArgs e) { TextBox1.AppendText("4"); } private void Button5_Click(object sender, EventArgs e) { TextBox1.AppendText("5"); } private void Button6_Click(object sender, EventArgs e) { TextBox1.AppendText("6"); } private void Button7_Click(object sender, EventArgs e) { TextBox1.AppendText("7"); } private void Button8_Click(object sender, EventArgs e) { TextBox1.AppendText("8"); } private void Button9_Click(object sender, EventArgs e) { TextBox1.AppendText("9"); } private void btnZero_Click(object sender, EventArgs e) { TextBox1.AppendText("0"); } private void btnEquals_Click(object sender, EventArgs e) { if (oper == null) { MessageBox.Show("You must enter a second number"); return; } num2 = TextBox1.Text; TextBox1.Text = Convert.ToString(calculateit(Convert.ToDouble(num1), Convert.ToDouble(num2), oper)); } private void btnAdd_Click(object sender, EventArgs e) { if (num1 == null) { num1 = TextBox1.Text; oper = "+"; TextBox1.Clear(); } else { num1 = Convert.ToString(calculateit(Convert.ToDouble(num1), Convert.ToDouble(num2), oper)); oper = "+"; TextBox1.Clear(); } } private void btnMinus_Click(object sender, EventArgs e) { if (num1 == null) { num1 = TextBox1.Text; } else { num1 = Convert.ToString(calculateit(Convert.ToDouble(num1), Convert.ToDouble(num2), oper)); oper = "-"; TextBox1.Clear(); } } private void btnMultiply_Click(object sender, EventArgs e) { if (num1 == null) { num1 = TextBox1.Text; } else { num1 = Convert.ToString(calculateit(Convert.ToDouble(num1), Convert.ToDouble(num2), oper)); oper = "*"; TextBox1.Clear(); } } private void btnDivide_Click(object sender, EventArgs e) { if (num1 == null) { num1 = TextBox1.Text; } else { num1 = Convert.ToString(calculateit(Convert.ToDouble(num1), Convert.ToDouble(num2), oper)); oper = "/"; TextBox1.Clear(); } } private void btnClear_Click(object sender, EventArgs e) { } public virtual double calculateit(double n1, double n2, string op) { switch (op) { case "+": return n1 + n2; case "-": return n1 - n2; case "*": return n1 * n2; case "/": return n1 / n2; } return 0; } } }