C++ (Cpp) CSPString::SetAt Examples

Example #1

File: MathParser.cpp Project: darwinbeing/trade

TokenTypes CMathParser::NextToken()//{ Gets the next Token from the Input stream }
{
	CSPString NumString;// : String[80];
	WORD TLen, NumLen; //, FormLen, Place;
	// int Check ;//: Integer;
	char Ch;//, FirstChar;
	BOOL Decimal ;
	TokenTypes ResultNextToken;

	while ((Position < FInput.GetLength()) && (FInput.GetAt(Position) == ' '))
		Position++;
	TokenLen = Position;
	if (Position >= FInput.GetLength())
	{
		ResultNextToken = EOL;
		TokenLen = 0;
		return ResultNextToken;
	}

	FInput.MakeUpper();

	Ch = FInput.GetAt(Position);
	if (Ch== '!')
	{
		ResultNextToken = ERR;
		TokenLen = 0;
		return ResultNextToken ;
	}

	if((Ch >= '0' && Ch <= '9') || Ch == '.')//   if Ch in ['0'..'9', '.'] then
	{
		NumString = "";
		TLen = Position;
		Decimal = FALSE;

		while ((TLen < FInput.GetLength()) &&
			((FInput.GetAt(TLen) >= '0' && FInput.GetAt(TLen) <= '9' ) ||
			((FInput.GetAt(TLen) == '.') && (!Decimal)))) 
		{
			NumString = NumString + FInput.GetAt(TLen);
			if (Ch == '.')// then
				Decimal = TRUE;
			TLen++;//Inc(TLen);
		}

		if ((TLen == 2) && (Ch == '.'))// then
		{
			ResultNextToken = BAD;
			TokenLen = 0;
			return ResultNextToken ;
		}

		if ((TLen < FInput.GetLength()) && ((FInput.GetAt(TLen)) == 'E'))// then
		{
			NumString = NumString + 'E';
			TLen++;
   
			if( FInput.GetAt(TLen) == '+' || FInput.GetAt(TLen) == '-')// in ['+', '-'] then
			{
				NumString.SetAt(TLen, FInput.GetAt(TLen));//= NumString + FInput[TLen];
				TLen++;
			}

			NumLen = 1;
			while ((TLen < FInput.GetLength()) && (FInput.GetAt(TLen) >= '0' && FInput.GetAt(TLen) <= '9') &&
				 (NumLen <= MP_MaxExpLen)) 
			{
				NumString = NumString + FInput.GetAt(TLen);
				NumLen++;//Inc(NumLen);
				TLen++;//Inc(TLen);
			}
		}

		if (NumString[0] == '.')// then
			NumString = '0' + NumString;

		CurrToken.Value = atof(NumString);
		//Val(NumString, CurrToken.Value, Check);

		/*//if (Check != 0 )
		{//    begin
			ErrorCode = MP_ErrMath;
			ErrorCode = ErrInvalidNum;
			Position += Pred(Check);
			//Inc(Position, Pred(Check));
		}//  end { if }
		else*/
		{//  begin
			ResultNextToken = NUM;
			Position += NumString.GetLength();
			//Inc(Position, System.Length(NumString));
			TokenLen = Position - TokenLen;
		}// end; { else }
		return ResultNextToken;
	}//end { if }
	else if ((Ch>='a' && Ch <= 'z')
	   || (Ch>='A' && Ch <= 'Z'))//in Letters then
	{//   begin
		if (IsFunc("ABS") ||
			IsFunc("ATAN") ||
			IsFunc("COS") ||
			IsFunc("EXP") ||
			IsFunc("LN") ||
			IsFunc("ROUND") ||
			IsFunc("SIN") ||
			IsFunc("SQRT") ||
			IsFunc("SQR") ||
			IsFunc("TRUNC")||
			IsFunc("NOT")||// then//EXPAND
			IsFunc("BOOL")||
			IsFunc("SGN")
			)
		{
			ResultNextToken = FUNC;
			TokenLen = Position - TokenLen;
			return ResultNextToken ;
		}

		if (IsFunc("MOD")) 
		{
			ResultNextToken = MODU;
			TokenLen = Position - TokenLen;
			return ResultNextToken ;
		}
		if (IsVar(CurrToken.Value))
		{
			ResultNextToken = NUM;
			TokenLen = Position - TokenLen;
			return ResultNextToken;
		}
		else 
		{
			ResultNextToken = BAD;
			TokenLen = 0;
			return ResultNextToken ;
		}
	}
	else 
	{//   begin
		switch(Ch)
		{
		case  '+' : ResultNextToken = PLUS; break;
		case  '-' : ResultNextToken = MINUS; break;
		case  '*' : ResultNextToken = TIMES; break;
		case  '/' : ResultNextToken = DIVIDE; break;
		case  '^' : ResultNextToken = EXPO; break;
		case  '(' : ResultNextToken = OPAREN; break;
		case  ')' : ResultNextToken = CPAREN; break;
		default:
		 ResultNextToken = BAD;
		 TokenLen = 0;
		 return ResultNextToken ;
	}//end; { case }
	Position++;
	TokenLen = Position - TokenLen;
	return ResultNextToken ;
	}//end; { else if }
}//end; { NextToken }