Algo lab/templates/postfix

Comments:

• Since the stack has to keep doubles, we change ValueType to double.
• We use iomanip to set precision.
• We use function stod to convert strings to doubles. (s-to-d)

#include <iostream>
#include <string>
#include <iomanip>

using namespace std;


int main()
{
  string buffer;

  do {
    cin >> buffer;
    if(buffer.at(0) == '=') {
      break;
    } else if((buffer.at(0) >= '0') && (buffer.at(0) <= '9')) {
      double val = stod(buffer);
      // *****************************
      // insert val into the top of the stack

    } else {
      // *****************************
      // buffer is an operator.
      // your code here

    }
  } while(true);
  cout << fixed << setprecision(4) << head->val << endl;
}