CODEWITHSUNDEEP
javatostring
user2976091
user2976091

Reputation: 233

Method toString() issue

I am creating application for canteen management. I must use the overriden method toString() somewhere so i put it in the class Menu for displaying total menu price.But i can`t call the method in my main(). How can i do this ? 

class Menu {

    private Soup soup;
    private SecondMeal second;
    private Dessert desert;

    public Menu(int soupId, int secId, int desId) {
        soup = new Soup(soupId);
        second = new SecondMeal(secId);
        desert = new Dessert(desId);
    }

    double price = soup.getPrice() + second.getPrice() + desert.getPrice();

    //here is my toString() method
    @Override
    public String toString() {
        String str = "Your menu price is " + price;
        return str;
    }

}

public class Testing {

    public static void main(String [] args) throws FileNotFoundException {

        Scanner scan = new Scanner(System.in);
        int soupId, secondId, desertId;

        do {
            System.out.println("Choose soup: ");
            Display.soupMenu();
            soupId = scan.nextInt();
        }
        while (soupId < 1 || soupId > 3);

        do {
            System.out.println("Choose second meal: ");
            Display.secondMenu();
            secondId = scan.nextInt();

        }
        while (secondId < 1 || secondId > 3);

        do {
            System.out.println("Choose dessert: ");
            Display.desertMenu();
            desertId = scan.nextInt();

        }
        while (desertId < 1 || desertId > 3);

        // here is the problem...
        System.out.println(Menu.toString()); // cannot make a static reference to the non-static method

    }
}

Upvotes: 1

Views: 155

Answers (5)

summer
summer

Reputation: 11

  • 1: You can't call a non-static method in a static method like main method.
  • 2: A non-static class can't call like --classname.method
  • 3 You're calling should be new Mean（parameters）, an object of a non-static class .

Upvotes: 1

Sotirios Delimanolis
Sotirios Delimanolis

Reputation: 279970

Note that this line

double price = soup.getPrice() + second.getPrice() + desert.getPrice();

will immediately fail. All instance fields are initialized before the constructor body is executed. At that point soup, second and desert are null. This will throw a NullPointerException. Instead, add that line at the end of your constructor.

double price;
...
public Menu(int soupId, int secId, int desId) {
    soup = new Soup(soupId);
    second = new SecondMeal(secId);
    desert = new Dessert(desId);
    price = soup.getPrice() + second.getPrice() + desert.getPrice();
}

For how to call the toString() method on an instance, see the other answers.

Upvotes: 1

Dylan Meeus
Dylan Meeus

Reputation: 5802

You have to create an instance of Menu and call "toString())" on that because it's not static.

Upvotes: 1

Masudul
Masudul

Reputation: 21961

At System.out.println toString should not manually call. It will call with the instance of object. Try to call like

 System.out.println(new Menu()); //toString will automatically call here.

Upvotes: 0

Hovercraft Full Of Eels
Hovercraft Full Of Eels

Reputation: 285403

Suggestions:

  • You need to create a Menu instance in the main method in order to call methods on it. I'd start there.
  • Your other classes should have toString() methods, including all of the food classes.
  • Within Menu's toString() method you could then iterate through the foods ordered, calling each one's toString() method in order to build up Menu's own String that it will return.

Upvotes: 0

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