About to make calculator

Question

Hello Everyone , i want to help about the calculator ,  i try to design calculator like the calculator with calculator of computer ....

 

The problem is that when try to add more than two numbers for example 5+3+2 ) the result will it 5 , get the last two numbers (3+2) and lost the 5

and the same problem with other operator * , / , - when try to count more than tree numbers ...

 

when i enter two numbers work perfect but there is this problem CAN YOU HELP ME ???

 

using System;

using System.Collections.Generic;

using System.ComponentModel;

using System.Data;

using System.Drawing;

using System.Linq;

using System.Text;

using System.Threading.Tasks;

using System.Windows.Forms;

namespace CalculationNew

{

public partial class Form1 : Form

{

string strFirstNumber;

bool check;

decimal num;

string strOperator;

string strFnumber;

decimal temp;

int i = 0;

public Form1()

{

InitializeComponent();

result.Text = "0";

}

private void button26_Click(object sender, EventArgs e)

{

}

//******************************************************************************************************************************************************

//The purpose of this is to put the numbers in to label called result

//note:is the numbers button

private void button14_Click(object sender, EventArgs e)

{

if (result.Text != "Invalid value")

{

if ((result.Text == "0") || (check == true))//check if the result is equal zero from the begin if it is then clean the label such as to write the numbers you want

{

result.ResetText(); //reset the label called result

}

Button btnNumbers = (Button)sender;//Use the command such as to use to all numbers from (0 - 9) allow to work public with use Button

result.Text = result.Text + btnNumbers.Text; //store the containts to label called result

num += Convert.ToDecimal(btnNumbers.Text);

check = false;//define this with false such as to if you want after press one operator and you want to write more than one numbers (for example 1*1.5 or 5.2*55555 and so on)

}

}

//********************************************************************************************************************************************************

//the purpose of this is to allow to enter at least one dot (.) in label called result

//++Note:is the dot button

private void button21_Click(object sender, EventArgs e)

{

if (result.Text != "Invalid value")

{

if (result.Text.Contains("."))

{

return;

}

result.Text += button21.Text;

}

}

//*********************************************************************************************************************************************************

//the purpose of this is to operators (addision ,subtraction , multiplication , division)

//++ Note : is the EqualButton

private void button20_Click(object sender, EventArgs e)

{

if (result.Text != "Invalid value")

{

Button btnOperator = (Button)sender;

strOperator = btnOperator.Text;

strFnumber = result.Text;

num = Decimal.Parse(result.Text);

check = true;

equestion.Text = equestion.Text + num + " " + strOperator;

// textBox2.Text

}

}

//*******************************************************************************************************************************************************

//the purpose of this is to calculate the total of numbers is the symbol equaland check thee operator

private void button19_Click(object sender, EventArgs e)

{

if (result.Text != "Invalid value")

{

switch (strOperator)//switch such as to check the operator

{

case "+":

{

num = Convert.ToDecimal(strFnumber) + Convert.ToDecimal(result.Text);//convert the string to decimal such as to calculate the numbers

result.Text = Convert.ToString(num);

} break;

case "-":

{

num =(Convert.ToDecimal(strFnumber) - Convert.ToDecimal(result.Text));//convert the string to decimal such as to calculate the numbers

result.Text = Convert.ToString(num);

} break;

case "/":

{

num = (Convert.ToDecimal(strFnumber) / Convert.ToDecimal(result.Text));//convert the string to decimal such as to calculate the numbers

result.Text = Convert.ToString(num);

} break;

case "*":

{

num = Convert.ToDecimal(strFnumber) * Convert.ToDecimal(result.Text);//convert the string to decimal such as to calculate the numbers

result.Text = Convert.ToString(num);

} break;

default:

break;

}

equestion.Text = " ";//clean the label called equestion

}

}

//******************************************************************************************************************************************************

//The purpose of this is to delete numbers from the begin to the end , (depend , how many numbers you want to delete)

//++note: Button "Backspace"

private void button6_Click(object sender, EventArgs e)

{

if (result.Text != "Invalid value")

{

if ((result.Text.Length > 0) && (result.Text != "0"))//check if there is at least one number

result.Text = result.Text.Remove(result.Text.Length - 1, 1);//this command delete from the begin to the end of the number

if (result.Text.Length == 0)//check if the lenght

result.Text = "0";

}

}

//*******************************************************************************************************************************************************

//the purpose of this is to reset only the label called result with zero

//++Note : is the button "CE"

private void button16_Click(object sender, EventArgs e)

{

if (result.Text == "Invalid value")

{

result.Text = "0";//reset the label called result

strFnumber = " ";//clear

// num = 0;

equestion.ResetText();//reset the label called equestion

}

if (result.Text!="0") //check if the result is not equal with zero then reset the label called result

result.ResetText();//reset the label called result

if(result.Text=="")//check if the result

result.Text = "0";

textBox1.Text = "";

}

//*************************************************************************************************************************************************

//The purpose of this is to resel all values

//++Note : is the button "C"

private void button15_Click(object sender, EventArgs e)

{

result.Text="0";//reset the label called result

strFnumber = " ";//clear

// num = 0;

textBox1.Text = "";

equestion.ResetText() ;//reset the label called equestion

}

//*************************************************************************************************************************************************

private void button10_Click(object sender, EventArgs e)

{

if (result.Text != "Invalid value")

{

if (Convert.ToDecimal(result.Text) >= 0)

{

double root = Math.Sqrt(Convert.ToDouble(result.Text));

result.Text = Convert.ToString(root);

equestion.Text = "sqrt(" + result.Text + ")" + " " + strOperator;

}

else

{

equestion.Text = "sqrt(" + result.Text + ")";

result.Text = "Invalid value";

}

}

}

private void result_Click(object sender, EventArgs e)

{

}

//****************************************************************************************************************************************************

}

}