//Проверка корректности скобок
private bool checkBrackets(string sourceStr)
{
Stack <int> posOfBrackets = new Stack <int>();
Stack <char> brackets = new Stack <char>();
for (int i = 0; i < sourceStr.Length; i++)
{
if (sourceStr [i] == '(')
{
brackets.Push('(');
posOfBrackets.Push(i);
}
if (sourceStr[i] == ')')
{
try{
brackets.Pop();
posOfBrackets.Pop();
} catch {
ErrorExeption.checkExeption(sourceStr[i], i);
return(false);
}
}
}
if (brackets.Count == 0)
{
return(checkOperations(sourceStr));
}
else
{
ErrorExeption.checkExeption(brackets.Pop(), posOfBrackets.Pop());
return(false);
}
}
public override float Eval()
{
if (right.Eval() == 0.0f)
{
ErrorExeption.customExeption("Error: Attempt to divide by 0");
throw new ArgumentException("Attempt to divide by 0");
}
return((right.Eval() != 0.0f) ? (left.Eval() / right.Eval()):float.MaxValue);
}
//Проверка операций
private bool checkOperations(string sourceStr)
{
string charsOfOperation = "+-/*.";
for (int i = 0; i < sourceStr.Length; i++)
{
if (charsOfOperation.Contains(sourceStr[i].ToString()) && charsOfOperation.Contains(sourceStr[i + 1].ToString()))
{
ErrorExeption.checkExeption(sourceStr[i], i);
return(false);
}
}
return(true);
}
//проверка выражения
public bool checkExpression()
{
string enabledChars = "0123456789+-/*.()";
for (int i = 0; i < sourceStr.Length; i++)
{
if (!enabledChars.Contains(sourceStr[i].ToString()))
{
ErrorExeption.checkExeption(sourceStr[i], i);
return(false);
}
}
return(checkBrackets(sourceStr));
}
//Парсинг числа
private Operation parseNumber()
{
Operation result = null;
float val = 0.0f;
int start = position;
while (position < sourceStr.Length && (char.IsDigit(sourceStr [position]) || sourceStr [position] == '.' || sourceStr [position] == 'e'))
{
++position;
}
try{
val = float.Parse(sourceStr.Substring(start, position - start));
} catch {
ErrorExeption.customExeption("Can't parse '" + sourceStr.Substring(start));
throw new ArgumentException("Can't parse '" + sourceStr.Substring(start));
}
result = new Number(val);
return(result);
}