calculate string expresion

[vbx_wx]

How can i calculate an expresion of type string:

strng eval = "129 + 23 - 54 * 2 / 4";

Any ideas?

[bunnyboy]

Reverse Polish Notation

[vbx_wx]

ok,i made the program but it only works with numbers from 0 to 9...if i have lets say 123 + 43 * 23 - 100....how can i push into the stack 123 then 43 then 23 then 100,not 1 2 3 4 3 2 3 1 0 0 ? Thanx

[bunnyboy]

Something like this maybe ... :)

void Load(const string& equation, stack<string>& st)
{
	for (string::size_type i(0); i < equation.size(); i++)
	{
		if (isdigit(equation[i]))
		{
			string number = "";
			number += equation[i];

			while (((i + 1) < equation.size()) && isdigit(equation[i + 1]))
			{
				number += equation[++i];
			}

			st.push(number);
		}
		else
		{

		}
	}
}