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For my first real project, I decided to go for a simple calculator.
I've got the calculator working as I want it to, so now I'd like some feedback and suggestions.
Please review it on coding style, readability, commenting etc. and give me tips on how I can improve and things I could do better/differently.
The form:
namespace Calculator
{
public partial class Form1 : Form
{
public string decimalSeparator = System.Globalization.NumberFormatInfo.CurrentInfo.CurrencyDecimalSeparator;
private Calculator calc = new Calculator();
public Form1()
{
InitializeComponent();
this.KeyPress += new KeyPressEventHandler(this.form1_KeyPress);
this.decimalSymbol.Text = decimalSeparator;
output.Focus();
}
// Handle keyboard input.
private void form1_KeyPress(object sender, KeyPressEventArgs e)
{
// Parse a number or decimal sign
if ((e.KeyChar >= '0' && e.KeyChar <= '9')
|| (e.KeyChar == decimalSeparator[0] && output.Text.Contains(decimalSeparator[0]) == false))
{
if (calc.Summed && calc.Operated == false)
{
calc.Reset();
clearOutput();
}
output.Text += e.KeyChar.ToString();
}
// Remove a character from the output if user pressed Backspace.
if (e.KeyChar == (char)Keys.Back && (output.Text.Length > 0))
output.Text = output.Text.Substring(0, output.Text.Length - 1);
switch (e.KeyChar)
{
// Set the operator to be used, if pressed on the keyboard
case '+':
case '/':
case '-':
case '*':
case '%':
calc.Operate(output.Text);
calc.Operator = e.KeyChar.ToString();
clearOutput();
break;
// Calculate the total if user pressed "=" or Enter.
case '=':
case (char)Keys.Return:
calc.Total(output.Text);
output.Text = calc.Sum.ToString();
break;
}
output.Focus();
}
private void clearOutput()
{
output.Text = "";
output.Focus();
}
// When the user clicks one of the number, decimal sign, or +/- buttons
private void number_Click(object sender, EventArgs e)
{
Control c = (Control)sender;
// Start over if the user enters a number instead of an operator after getting the total sum.
if (calc.Summed && calc.Operated == false)
calc.Reset();
// Skip if the textbox already contains a decimal sign
if (c.Text == decimalSeparator && output.Text.Contains(decimalSeparator[0]))
return;
// The +/- button toggles positive/negative number.
else if (c.Text == "+/-")
{
if (output.Text.StartsWith("-"))
{
char[] a = { '-' };
output.Text = output.Text.TrimStart(a);
}
else
output.Text = "-" + output.Text;
}
// append number or decimal sign to the textbox
else
output.Text += c.Text;
output.Focus();
}
// When user clicks on one of the operator buttons, parse the contents of the textbox to
// a temporary variable, set the operator to be used on the following number, and then
// clear the textbox.
private void function_Click(object sender, EventArgs e)
{
Control c = (Control)sender;
calc.Operate(output.Text);
calc.Operator = (sender as Control).Text;
clearOutput();
}
// Calculate the total sum when user clicks button labeled "=".
private void sumEquals_Click(object sender, EventArgs e)
{
calc.Total(output.Text);
output.Text = calc.Sum.ToString();
output.Focus();
}
// Reset the calculator when user clicks the button labeled "C".
private void reset_Click(object sender, EventArgs e)
{
calc.Reset();
clearOutput();
}
}
}
The Calculator class:
namespace Calculator
{
public class Calculator
{
public string Operator;
private decimal decimal1;
private decimal decimal2;
private decimal sum;
public decimal Sum
{
get { return sum; }
}
private bool summed = false;
public bool Summed
{
get { return summed; }
}
private bool operated = false;
public bool Operated
{
get { return operated; }
}
public decimal Calculate(decimal d1, decimal d2)
{
decimal sum = 0;
switch (Operator)
{
case "/":
if (d2 == 0)
{
MessageBox.Show("Can't divide by zero");
return d1;
}
sum = d1 / d2;
break;
case "*":
sum = d1 * d2;
break;
case "-":
sum = d1 - d2;
break;
case "+":
sum = d1 + d2;
break;
case "%":
if (d2 == 0)
{
MessageBox.Show("Can't divide by zero");
return d1;
}
sum = d1 % d2;
break;
}
return sum;
}
public void Operate(string output)
{
// if there has already been a previous math operation
if (operated)
{
Decimal.TryParse(output, out decimal2);
decimal1 = Calculate(decimal1, decimal2);
}
// Otherwise
else
Decimal.TryParse(output, out decimal1);
operated = true;
summed = false;
}
public void Total(string output)
{
// if the user presses "=" or Enter again, repeat the last operation on the current sum
if (summed && operated == false)
decimal1 = sum;
// Otherwise, calculate the previous and current number together.
else
{
Decimal.TryParse(output, out decimal2);
operated = false;
}
sum = Calculate(decimal1, decimal2);
summed = true;
}
public void Reset()
{
sum = 0;
operated = false;
summed = false;
}
}
}
Edit: Added language and type of project in the topic description
This post has been edited by groer: 22 May 2010 - 12:08 PM
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