Task9.cpp

#include <string>
#include<sstream>
#include<exception>
#include <iostream>
using namespace std;

class Polish_Converter {
private:
	enum Op_sym {
		PLUS = '+',
		MINUS = '-',
		MULTIP = '*',
		DIVID = '/',
		POW = '^',
		L_BRACE = '(',
		R_BRACE = ')',
		SPACE_SYM = ' '
	};
	string input_string;
	string output_string;
	string op_stack;
protected:
	char last_sym;
public:
	Polish_Converter() = default;
	Polish_Converter(string in) : input_string(in){}
	Polish_Converter(const Polish_Converter&) = default;
	~Polish_Converter() { input_string.clear(); output_string.clear(); op_stack.clear(); }

	string Get_Input_String()const;
	string Get_Output_String()const;
	void Set_Input_String(string);
	void Convert_To_Polish();

	friend ostream& operator<<(ostream&, const Polish_Converter&);
	friend istream& operator>>(istream&, Polish_Converter&);
};

/*
*@[brief]: friend overloaded output operator;
*@[in]: ostream object for output and const reference to class object
*@[out]: ostream reference for chain output
*/
ostream& operator<<(ostream& out, const Polish_Converter& obj) { 
	out << obj.output_string;
	return out;
}

/*
*@[brief]: friend overloaded input operator;
*@[in]: istream object for input and reference to class object
*@[out]: istream reference for chain input
*/

istream & operator>>(istream & in, Polish_Converter & obj)
{
	
	try {
		getline(in, obj.input_string);

		return in;
	}
	catch (exception& ex) {
		cout << "Whoaa we got exception here, ty another input but restart program first\n Error: " << ex.what();
		exit(true);
	}
}

/*
*@[brief]: Function convert string expr to RPN form
*/
void Polish_Converter::Convert_To_Polish()
{
	op_stack.clear();
	output_string.clear();
	last_sym = 0;
	for (auto x : input_string) {
		if (isspace(x)) {
			continue;
		}
		if (isalpha(x)||isdigit(x)) {
			output_string.push_back(x);
		}
		switch (x) {
		case PLUS:
		case MINUS:
			output_string.push_back(SPACE_SYM);
			if (op_stack.empty()) {
				op_stack.push_back(x);
			}
			else {
				last_sym = op_stack.back();
				switch (last_sym) {
				case PLUS:
				case MINUS:
				case MULTIP:
				case DIVID:
				case POW:
					output_string.push_back(op_stack.back());
					op_stack.pop_back();
					op_stack.push_back(x);
					output_string.push_back(SPACE_SYM);
					break;
				case L_BRACE:
					op_stack.push_back(x);
					break;
				}
			}
			break;
		case MULTIP:
		case DIVID:
			output_string.push_back(SPACE_SYM);
			if (op_stack.empty()) {
				op_stack.push_back(x);
			}
			else {
				last_sym = op_stack.back();
				switch (last_sym) {
				case MULTIP:
				case DIVID:
				case POW:
					output_string.push_back(op_stack.back());
					op_stack.pop_back();
					op_stack.push_back(x);
					output_string.push_back(SPACE_SYM);
					break;
				case L_BRACE:
					op_stack.push_back(x);
					break;
				}
			}
			break;
		case POW:
			output_string.push_back(SPACE_SYM);
		case L_BRACE:
			op_stack.push_back(x);
			break;
		case R_BRACE:
			int tmp_count = 0;
			output_string.push_back(SPACE_SYM);
			string::iterator b = op_stack.end()-1;
			for (; *b != L_BRACE; --b) {
				output_string.push_back(*b);
				output_string.push_back(SPACE_SYM);
				tmp_count++;
			}
			tmp_count++;
			op_stack.erase(op_stack.end() - tmp_count, op_stack.end());
			break;
		}
	}
	if (!op_stack.empty()) {
		string::iterator b = op_stack.end() - 1;
		for (; b != op_stack.begin(); --b) {
			output_string.push_back(*b);
		}
		output_string.push_back(*b);
		output_string.push_back(SPACE_SYM);
		op_stack.clear();
	}
}
/*
*@[brief]: Helper function that returns input string
*@[out]: copy of private member that holds user expr
*/
string Polish_Converter::Get_Input_String() const
{
	return input_string;
}
/*
*@[brief]: Helper function that returns converted expr
*@[out]: copy of private member that holds RPN expr
*/
string Polish_Converter::Get_Output_String() const
{
	return output_string;
}
/*
*@[brief]: Helper function that sets input string;
*@[in]: user input string;
*/
void Polish_Converter::Set_Input_String(string in)
{
	input_string = in;
}

void main() {
	Polish_Converter obj;
	obj.Set_Input_String("((a + b)/(3*2/4^3))");
	obj.Convert_To_Polish();
	cout << obj << endl;

	Polish_Converter * p_obj = new Polish_Converter("1 2 + 2");

	p_obj->Convert_To_Polish();
	cout << *p_obj;
	delete p_obj;
	cout << "\n\n\nEnter Expression: ";
	cin >> obj;
	//obj.Set_Input_String("((a + b) / (3 * 2 / 4 ^ 3))");
	obj.Convert_To_Polish();
	cout << "\n\n" << obj << "\n";

}