public void Append(string text)
{
if (ExpressionValidator.IsSpecialSymbol(text) && !CanAppendSpecialSymbol(text))
{
return;
}
_resultView.Text += text;
}
private string ReformatExpression(string exp)
{
const string validMulSign = "*";
exp = exp.Replace(Calculator.Mul, validMulSign);
var lastSymbol = exp[exp.Length - 1];
if (ExpressionValidator.IsSpecialSymbol(lastSymbol))
{
exp = exp.Substring(0, exp.Length - 1);
}
return(exp);
}
private bool CanAppendSpecialSymbol(string text)
{
var result = _resultView.Text;
if (string.IsNullOrEmpty(result))
{
return(false);
}
var lastSymbol = result[result.Length - 1];
if (ExpressionValidator.IsSpecialSymbol(lastSymbol))
{
return(false);
}
return(true);
}
