#include <iostream>
#include <string>

using namespace std;

class Calc {

public:
	int calculate( int a, char op, int b );
};

int Calc::calculate( int a, char op, int b )
{
	switch (op) {
	case '+':
		return a + b;
		break;
	case '-':
		return a - b;
		break;
	case '*':
		return a * b;
		break;
	case '/':
		if( b == 0 ) {
			cout << "Divided by zero" << endl;
			return -1;
		} else
			return a/b;
		//return b ? a / b : -1;
		break;
	default:
		cout << "Unknown operator: " << op << endl;
		system("pause");
		exit(1);
	}
}

int main()
{
	Calc c;
	int a, b;
	char op;
	while(1) {
		cout << "Please enter <val> <op> <val>:"; 
		cin >> a >> op >> b;
		//int result = c.calculate( a, op, b );

		cout << "result is " << c.calculate( a, op, b ) << endl;
	}
	system("pause");

}