#include  <iostream>

using namespace std;

int getLength(char first[]);
int fromCharToInt(char arr[]);
int Pow(int num, int pow);

int main()
{
	char* expression = new char[100];
	char* firstSum = new char[35];

	int firstNum = 0;

	while (true)
	{
		bool isValid = true;
		cout << "Enter an expression to calculate or write 'exit' to close the program:" << endl;

		cin.getline(expression, 100);
		char operation;

		if (expression[0] == 'e' && expression[1] == 'x' && expression[2] == 'i' && expression[3] == 't'&&expression[4]=='\0')
			return 0;

		//to  do validation _|_

		int sizeOfArray = getLength(expression);

		for (int i = 0; i < sizeOfArray - 1; i++)
		{
			if (expression[0] == ' ')
			{
				cout << "This expression is invalid" << endl;
				isValid = false;
				break;
			}

			while (expression[i] != ' ')
			{
				int n = 0;
				firstSum[n] = expression[i];
				n++;

				if (expression[i] == '+' || expression[i] == '-' || expression[i] == '*' || expression[i] == '/' || expression[i] == '!')
				{
					operation = expression[i];
				}
			}

		//to  do vsichko ostanalo

			if (expression[i] == ' ')
			{
				i++;
				continue;
			}


		}
		if (!isValid)
			continue;

		break;
	}




	return 0;
}

int getLength(char first[])
{
	int count = 0;
	char* p = first;
	while (*p != '\0')
	{
		count++;
		p++;
	}
	return count;
}

int fromCharToInt(char arr[])
{
	int size = getLength(arr);
	int number=0;
	int pow = size-1;

	for (int i = 0; i < size; i++)
	{
		number = (arr[i] - '0') * Pow(10,pow--);
	}
	return number;
}

int Pow(int num, int pow)
{
	int result = 1;

	for (int i = 0; i < pow; i++){
		result *= num;
	}

	return result;
}