/// <summary>
/// fill multiply operators between:
/// constant | number;
/// number | constant;
/// constant | constant;
/// ) | constant, number, (;
/// constant, number | (;
/// constant, number, ) | function;
/// (if there is no operator)
/// </summary>
/// <param name="equation">string containing equation</param>
/// <returns>equation with filled multiply operators where are required</returns>
private static string FixMissingMultiplyOperator(string equation)
{
for (int i = equation.Length - 1; i > 0; --i)
{
char ch1 = equation[i - 1];
char ch2 = equation[i];
// constant | number
if ((StringControl.IsLastCharOfConstantConstant(ch1) &&
StringControl.GetConstantStringByLastChar(equation.Substring(0, i)) != string.Empty
&& StringControl.IsNumberChar(ch2))
// number | constant
|| (StringControl.IsNumberChar(ch1)
&& StringControl.IsFirstCharOfConstantConstant(ch2) &&
StringControl.GetConstantString(equation.Substring(i)) != string.Empty)
// constant | constant
|| (StringControl.IsLastCharOfConstantConstant(ch1) &&
StringControl.GetConstantStringByLastChar(equation.Substring(0, i)) != string.Empty
&& StringControl.IsFirstCharOfConstantConstant(ch2) &&
StringControl.GetConstantString(equation.Substring(i)) != string.Empty)
// ) | constant number (
|| (ch1 == ')'
&& (StringControl.IsNumberChar(ch2) ||
StringControl.IsFirstCharOfConstantConstant(ch2) &&
StringControl.GetConstantString(equation.Substring(i)) != string.Empty ||
ch2 == '('))
// constant number | (
|| ((StringControl.IsNumberChar(ch1) ||
StringControl.IsLastCharOfConstantConstant(ch1) &&
StringControl.GetConstantStringByLastChar(equation.Substring(0, i)) != string.Empty)
&& ch2 == '(')
// constant number ) | function
|| ((StringControl.IsNumberChar(ch1) ||
StringControl.IsLastCharOfConstantConstant(ch1) &&
StringControl.GetConstantStringByLastChar(equation.Substring(0, i)) != string.Empty ||
ch1 == ')')
&& Operators.IsFirstCharOfFunctionOperator(ch2) &&
Operators.GetOperator(equation.Substring(i)) != OperatorsEnum.None)
)
{
equation = equation.Insert(i, Strings.Multiply);
}
}
return(equation);
}
/// <summary>
/// will check equation if there are no unknown characters
/// </summary>
/// <param name="equation">string containing equation</param>
/// <returns>true if equation does not contains unknown character else false if contains</returns>
private bool CheckUnknownCharacter(string equation)
{
int i = 0;
while (equation.Length > i)
{
// check if is constant -> the it is good :)
if (StringControl.IsFirstCharOfConstantConstant(equation[i]) &&
StringControl.GetConstantString(equation.Substring(i)) != string.Empty)
{
i += StringControl.GetConstantString(equation.Substring(i)).Length;
}
else if (StringControl.IsNumberChar(equation[i]))
{
// get string of number characters
string substring = string.Empty;
do
{
substring += equation[i++];
}while (equation.Length > i && StringControl.IsNumberChar(equation[i]));
// check if string can be converted to number
try
{
StringToDouble(substring, ref _error);
}
catch
{
return(false);
}
}
else
{
// get string of all another characters
string substring = string.Empty;
do
{
substring += equation[i++];
}while (equation.Length > i && !StringControl.IsNumberChar(equation[i]) &&
!(StringControl.IsFirstCharOfConstantConstant(equation[i]) &&
StringControl.GetConstantString(equation.Substring(i)) !=
string.Empty));
if (!CheckStringOfOperators(substring))
{
_error = ErrorsEnum.InvalidSequenceOfCharacters;
return(false);
}
}
}
return(true);
}