#include <iostream>
#include <iomanip>
#include <string>
using namespace std;



bool IsvalidNumForBase(int, int, int);
int baseToDecimal(int, int);
void decimalToBase(int, int, int &, int &);
int decimalOperation(int decinum1, int decinum2, char o);

// Variables
int base = 0; // the base number the user will enter
int num1, num2; // integers that must be less than the base
int decinum1, decinum2; // the decimal value for nums 1 and 2
bool IsvalidNum = true;
char op;
int resultWithNoTrailingZero, numTrailingZeros;
int main()
{
	int opResult;
	cout << "Enter the base: " << endl;
	cin >> base;


	cout << "Enter the first number: " << endl;
	cin >> num1;

	cout << "Enter the second number: " << endl;
	cin >> num2;

	cout << "List of operations: " << endl;
	cout << "+" << endl;

	cout << "-" << endl;

	cout << "*" << endl;

	cout << "/" << endl;

	cout << "Enter your choice of operation: " << endl;
	cin >> op;

	cout << endl;
	cout << "OUTPUT: " << endl;

	IsvalidNum = IsvalidNumForBase(num1, num2, base);
	IsvalidNumForBase(num1, num2, base);

	if (base < 2 || base > 9)
	{
		cout << "The base is not valid. " << endl;
	}

	else if (!IsvalidNum)
	{
		cout << "The number is not valid for base " << base << endl;
	}
	else if (op != '+' && op != '-' && op != '*' && op != '/')
	{
		cout << "The operation is not valid " << endl;
	}
	else
	{
		cout << "The number is valid for base " << base <<endl;

		decinum1 = baseToDecimal(base, num1);
		baseToDecimal(base, num1);
		cout << "Decimal value of the first number = " << decinum1 << endl;

		decinum2 = baseToDecimal(base, num2);
		baseToDecimal(base, num2);
		cout << "Decimal value of the second number = " << decinum2 << endl;


		if (decinum2 == 0 && op == '/')
		{
			cout << "Divide by zero error!!! " << endl;
			cout << "Check the symbol and the operands" << endl;
		}
		else
		{
			opResult = decimalOperation(decinum1, decinum2, op);
			cout << "Result in decimal = " << opResult << endl;

			decimalToBase(opResult, base, resultWithNoTrailingZero, numTrailingZeros);
			cout << "Result in base " << base << " = " << resultWithNoTrailingZero;

			while (numTrailingZeros > 0)
				cout << "0";
				numTrailingZeros--;
		}
		cout << endl;
	}
	return 0;
}
	//params: (in, in)
	int baseToDecimal(int base, int num)
	{
		int dec = 0;
		int digit = 0; // will hold each digit of the number
		int counter = 0;
		while (num > 0)
		{
			digit = num % 10;
			dec = (digit * (pow(base, counter))) + dec;
			num = num / 10;
			counter++;
		}

		return dec;
	}
	//params: (in, in, in/out, in/out)
	void decimalToBase(int opResult,int base,int& resultWithNoTrailingZero, int& numTrailingZeros)
	{
		int remainder = 0;
		while (opResult > 0)
		{
			remainder = opResult % base;
			resultWithNoTrailingZero = resultWithNoTrailingZero * 10 + remainder;
			if (resultWithNoTrailingZero == 0)
				numTrailingZeros++;
			opResult = opResult / base;
		}
	}

	//params: (in, in, in)
	int decimalOperation(int decinum1, int decinum2, char op)
	{
		int opResult = 0;
		if (op == '+')
		{
			opResult = decinum1 + decinum2;
		}
		else if (op == '-')
		{
			opResult = decinum1 - decinum2;
		}
		else if (op == '*')
		{
			opResult = decinum1 * decinum2;
		}
		else
		{
			opResult = decinum1 / decinum2;
		}
		return opResult;
	}
	// params: (in, in)
	bool IsvalidNumForBase(int num1, int num2, int base)
	{
		int digit = 0;
		while (num1 > 0)
		{
			digit = num1 % 10;
			num1 /= 10;

			if (digit >= base)
			{
				return false;
			}
		}
		while (num2 > 0)
		{
			digit = num2 % 10;
			num2 /= 10;

			if (digit >= base)
			{
				return false;
			}
		}
		return true;
	}