#include <iostream>
#include <limits>

using namespace std;

int main(){
	
	double firstNumber = 0.0, secondNumber = 0.0, result = 0.0;
	char operation = 'x';	
	
	while (true){
	
		try{
		
			cout << "Birinci sayi, isaret , ikinci sayi :";
			cin >> firstNumber >> operation >> secondNumber;
          
            if(cin.fail())
            {
              cin.clear();
              cin.ignore(numeric_limits<streamsize>::max(),'\n');
              throw string("Hatali Giris");
            }
			
			switch (operation){
				case '+':
					result = firstNumber + secondNumber;
						break;
				case '-':
					result = firstNumber - secondNumber;
						break;
				case '*':
					result = firstNumber * secondNumber;
						break;
				case '/':
					result = firstNumber / secondNumber;
						break;
						
				default:
					result = '0';
				}
		}
				
		catch(string msg)
        {
          cout << msg << endl;
          continue;
		}
		
		cout << result << endl;
		
		}	
	}