private string BuildInfix(bool tokenize)
{
int i = 0;
var s = new Stack <BuildInfixNode>();
var open = new BuildInfixNode("(");
var close = new BuildInfixNode(")");
while (i < TokenizedPostfix.Length)
{
char c = TokenizedPostfix[i++];
if (c == '{')
{
if (TokenizedPostfix[i] == 'A')
{
int j = i + 3; // parsing an argument, j points at the 1st digit of the argument's index
int k = j + 1;
while (TokenizedPostfix[k] != '}')
{
++k;
}
if (tokenize)
{
s.Push(new BuildInfixNode(TokenizedPostfix.Substring(i - 1, k - i + 2)));
}
else
{
s.Push(new BuildInfixNode(_argBook[int.Parse(TokenizedPostfix.Substring(j, k - j))]));
}
i = k + 1;
}
else
{
int j = i + 1; // parsing a const number, j points at the number's 1st digit
while (TokenizedPostfix[j] != '}')
{
++j;
}
if (tokenize)
{
s.Push(new BuildInfixNode(TokenizedPostfix.Substring(i - 1, j - i + 2)));
}
else
{
s.Push(new BuildInfixNode(TokenizedPostfix.Substring(i, j - i)));
}
i = j + 1;
}
}
else if (c == 'N')
{
s.Push(new BuildInfixNode("-", s.Pop()));
}
else if (c == 'P')
{
s.Push(new BuildInfixNode("+", s.Pop()));
}
else
{
var x1 = s.Pop(); // merges a binary operator with two of its operands
var x2 = s.Pop();
s.Push(new BuildInfixNode(open, x2, c.ToString(), x1, close));
}
}
return(s.Pop().ToString());
}
public decimal Compute(params decimal[] args)
{
if (args.Length != ArgCount)
{
throw new ArgumentException("Incorrect argument count.");
}
int i = 0;
var s = new Stack <decimal>();
while (i < TokenizedPostfix.Length)
{
char c = TokenizedPostfix[i++];
if (c == '{')
{
if (TokenizedPostfix[i] == 'A')
{
int index = TokenizedPostfix[i += 3] - '0';
++i;
while (TokenizedPostfix[i] != '}')
{
index *= 10;
index += TokenizedPostfix[i++] - '0';
}
s.Push(args[index]);
++i;
}
else
{
int j = i + 1;
while (TokenizedPostfix[j] != '}')
{
++j;
}
s.Push(decimal.Parse(TokenizedPostfix.Substring(i, j - i)));
i = j + 1;
}
}
else if (c == 'N')
{
s.Push(-s.Pop());
}
else if (c == 'P')
{
s.Push(Math.Abs(s.Pop()));
}
else
{
var x1 = s.Pop();
var x2 = s.Pop();
if (c == '+')
{
s.Push(x2 + x1);
}
else if (c == '-')
{
s.Push(x2 - x1);
}
else if (c == '*')
{
s.Push(x2 * x1);
}
else if (c == '/')
{
if (x1 == 0)
{
throw new ArithmeticException("Division by zero.");
}
s.Push(x2 / x1);
}
else if (c == '^')
{
if (x2 < 0 && ((x1 > 0 && x1 < 1) || (x1 > -1 && x1 < 0)))
{
throw new ArithmeticException("Incorrect exponentation: " + x2.ToString() + "^" + x1.ToString() + ".");
}
s.Push((decimal)Math.Pow((double)x2, (double)x1));
}
else if (c == '%')
{
if (x1 == 0)
{
throw new ArithmeticException("Division by zero.");
}
s.Push(x2 % x1);
}
}
}
return(s.Pop());
}
