pqowieurytlaksjdhfgmznxbcv

#include <iostream>
using namespace std;

enum token{
  plus, minus, mult, divi, squrt, expon, ln, empty, error, number
};

struct stackComponent{
  bool flag;
  double number;
  token operation;
};
stackComponent emptycomponent = {true, 0, number};
stackComponent errorcomponent = {true, 0, error};
bool compare(stackComponent a, stackComponent b){
  if(a.flag == b.flag && a.number == b.number && a.operation == b.operation) return true;
  else return false;
}

class stack{
  stackComponent stck[100];
  int tracker;
public:
  stack();
  stackComponent pop();
  void push(stackComponent object);
};
stack::stack(){
  for(int i = 0; i < 100; i++) stck[i] = emptycomponent;
  tracker = 0;
}
stackComponent stack::pop(){
  if(!tracker) return errorcomponent;
  else{
    tracker--;
    stackComponent value = stck[tracker];
    stck[tracker] = emptycomponent;
    return value;
  }
}
void stack::push(stackComponent object){
  stck[tracker] = object;
  tracker++;
}

class calculator{
  stack equation;
  stack solution;
  void add();
  void subtract();
  void multiply();
  void divide();
  void squareroot();
  void exponent();
  void logarithm();
public:
  double calculate();
  void loadeq();
};
void calculator::add(){
  stackComponent opA = solution.pop();
  stackComponent opB = solution.pop();
  if(!compare(opA, emptycomponent) || !compare(opA, errorcomponent)) return;
  if(!compare(opB, emptycomponent) || !compare(opB, errorcomponent)) return;
  solution.push({false, opA.number + opB.number, number});
  return;
}

int main(){
  stack s;
  s.push({false, 0, empty});
  s.push({false, 1, empty});
  s.push({false, 2, empty});
  s.push({false, 3, empty});
  printf("%f\n", s.pop().number);
  printf("%f\n", s.pop().number);
  printf("%f\n", s.pop().number);
  printf("%f\n", s.pop().number);
}