using System; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Drawing; using System.Linq; using System.Text; using System.Windows.Forms; namespace calculator { { public partial class Form1 : Form double a = 0; double b = 0; bool c= false ; string d; public Form1() { } InitializeComponent(); private void Form1_Load(object sender, EventArgs e) { } private void button9_Click(object sender, EventArgs e) { 

if ( c ==true ) { textBox1 .Text =""; c=false ; } textBox1.Text+="1"; } private void button10_Click(object sender, EventArgs e) { } if(c==true ) { } textBox1.Text=""; c=false ; textBox1.Text+="2"; private void button11_Click(object sender, EventArgs e) { } if (c==true ) { } textBox1 .Text =""; c=false ; textBox1 .Text +="3"; private void button5_Click(object sender, EventArgs e) { 

if(c==true ) { } textBox1.Text=""; c=false ; textBox1.Text+="4"; } private void button6_Click(object sender, EventArgs e) { } if(c==true ) { } textBox1.Text=""; c=false ; textBox1.Text+="5"; private void button7_Click(object sender, EventArgs e) { if(c==true ) { textBox1.Text=""; c=false ; }