public class Temperature {

    private double temperature;
    private char scale;

    Temperature(double temperature, char scale)
    {

       set(temperature, scale);

    }

    private Temperature(double v) {
    }

    private void set(double temperature, char scale)
    {
        if(scale == 'K' && temperature < 0 ) {
            System.out.println("Error, Kelvin cannot be less than 0.");
            System.exit(0);
        }if(scale == 'C' && temperature < -273.15) {
        System.out.println("Error, Celsius cannot be less than absolute 0.");
        System.exit(0);
    }if(scale == 'F' && temperature <-459.67){
        System.out.println("Error, Fahrenheit cannot be less than absolute 0.");
        System.exit(0);
    }
        this.temperature=temperature;
        this.scale=scale;
    }
    private Temperature() {
    }
    Temperature toKelvin()
    {
        double converted_Temp;

        switch(scale) {
            case 'C': {
                converted_Temp = (temperature + 273.15);
                return new Temperature(converted_Temp, 'K');
            }

            case 'F': {
                converted_Temp = ((temperature - 32) * 5.0 / 9.0 + 273.15);
                return new Temperature(converted_Temp, 'K');
            }
        }
        if (temperature < 0)
        {
            System.out.println("K cannot be < 0");
            System.exit(0);
        }

        return new Temperature();
    }

    Temperature toCelsius()
    {
        double converted_Temp;

        switch (scale) {
            case 'K':
                converted_Temp = temperature - 273.15;
                return new Temperature(converted_Temp, 'C');


            case 'F':
                converted_Temp =  ((temperature - 32) * 5.0 / 9.0);
                return new Temperature(converted_Temp, 'C');
            }


        if(temperature < -273.15)
        {
            System.out.println("C cannot be < -273.15");
            System.exit(0);
        }

        return new Temperature();
    }

     Temperature toFahrenheit()
    {
        double converted_Temp;
        switch (scale) {
            case 'K':
                converted_Temp =  (temperature - 273.15) * 9.0 / 5.0 + 32;
                return new Temperature(converted_Temp, 'F');

        case 'C':
                converted_Temp = (temperature * 9.0 / 5.0 + 32);
                return new Temperature(converted_Temp, 'F');
            }

            if (temperature < -459.67) {
                System.out.println("F cannot be < -459.67");
                System.exit(0);
            }
        return new Temperature();
    }


    Temperature add(Temperature n)
    {
        Temperature result = new Temperature();
        result.set(temperature, scale);
        Temperature temp1 = this.toKelvin();
        Temperature temp2 = n.toKelvin();
        Temperature temp3 = n.toKelvin();
        Temperature temp4 = n.toKelvin();
        result = new Temperature(temp1.temperature + temp2.temperature + temp3.temperature + temp4.temperature);
        return result;
    }

    Temperature subtract(Temperature z) {
        Temperature temp2 = this.toKelvin();
        Temperature temp1 = z.toKelvin();
        new Temperature( temp2.temperature - temp1.temperature);
        return new Temperature(temp1.temperature - temp2.temperature, 'K');
    }
    Temperature multiply(Temperature n)
    {
        Temperature temp1 = this.toKelvin();
        Temperature temp2 = n.toKelvin();

        return new Temperature(temp1.temperature*temp2.temperature, 'K');
    }

    Temperature divide()
    {
        Temperature tempAve = toKelvin();
        double avgtemp =(tempAve.temperature/ 5);

        return new Temperature(avgtemp, 'K');
    }

    boolean equals(Temperature n)
    {
        return this.temperature == n.temperature && this.scale == n.scale;
    }
    public String toString()
    {
        return "Temperature " + temperature + " is measured in " + scale;
    }

}