#pragma once

#include <string>
#include <stack>

class RPN
{
public:
	RPN();
	RPN(std::string expression);
	RPN(const RPN &other);
	~RPN();
	RPN &operator=(const RPN &other);
	void setExpression(std::string expression);
	int evaluate();

	class NoExpressionException : public std::exception
	{
	public:
		const char *what() const noexcept override;
	};

	class InvalidExpressionException : public std::exception
	{
	public:
		const char *what() const noexcept override;
	};

	class DivisionByZeroException : public std::exception
	{
	public:
		const char *what() const noexcept override;
	};

	class InvalidCharacterException : public std::exception
	{
	public:
		const char *what() const noexcept override;
	};

private:
	std::string _expression;

	bool isWellformed() const;
	bool isOperator(char c) const;
	int applyOperator(int a, int b, char op) const;
	void printStack(std::stack<int> stack) const;
};