/* Only excepted characters are 4 operators, brackets, dot and digit number which can be contained in expression
* Only start with number, negative number or open bracket. Case (*)6 + 7 - 8 is invalid
* Only end with number, close bracket. Case 7 * 9 (+) is invalid
* All open brackets has close bracket of itself and vice versa. Assume open bracket is +1 and close bracket is -1, if number is negative or final number is not 0, expression will be wrong.
* String for number must be a number and it's in range of decimal
* A number is not more than 1 dot and minus is in front if it has
* Not 2 operators near by even minus, it need bracket such as 8+(-3)
* Division by Zero is optional, but it should check in program
*/
public static ErrorItem ExpValidate(string exp)
{
string expTrimed = exp.Replace(" ", string.Empty);
ErrorItem validReturn = ValideExceptedCharacters(expTrimed);
if (validReturn.Code != 0)
{
return(validReturn);
}
validReturn = ValidBracket(expTrimed);
if (validReturn.Code != 0)
{
return(validReturn);
}
//todo:
return(new ErrorItem {
Code = 0, Msg = string.Empty
});
}
