import java.io.BufferedReader;
import java.io.InputStreamReader;

class CalculatorInput{
    BufferedReader stream;
    CalculatorEngine engine;

    CalculatorInput(CalculatorEngine e){
        InputStreamReader input = new InputStreamReader(System.in);
        stream = new BufferedReader(input);
        engine = e;
    }

    void run() throws Exception{
        System.out.print("calculadora \n");
     for(;;){
            System.out.print("[" + engine.display() + "]");
            String m = stream.readLine();
            if(m == null) break;
            if(m.length() > 0){
                char c = m.charAt(0);
                if (c == '+')
                    engine.add();
                else if (c == '-')
                    engine.subtract();
                else if (c == '*')
                    engine.multiply();
                else if (c == '/')
                    engine.divide();
                else if (c >= '0' && c <= '9')
                    engine.digit(c - '0');
                else if (c == '=')
                    engine.compute();
                else if (c == 'c' || c == 'C')
                    engine.clear();
            }
        }
    }
    public static void main (String arg[]) throws Exception {
     CalculatorEngine e = new CalculatorEngine();
        CalculatorInput x = new CalculatorInput(e);
        x.run();
    }
}