CODEWITHSUNDEEP
java
fufupug
fufupug

Reputation: 53

How to call a method from another class with no constructor

I'm having a bit of trouble on a program at school.

I have to call a method called factorial in my FactorialCalculator class through a method called factorial in my BCD class. Normally, I would do something like this:

FactorialCalculator newCalc = new FactorialCalculator(8);

However, factorial is the only method in the FactorialCalculator class, and I am not allowed to make any more methods, including a constructor.

Any suggestions?

Upvotes: 5

Views: 3281

Answers (5)

julianwki
julianwki

Reputation: 422

First, you always have the standard constructor, which takes no parameters. So you can instatiate FactorialCalculator and then call its factoral-Method.

Upvotes: 1

Mohammed Aouf Zouag
Mohammed Aouf Zouag

Reputation: 17132

Create it as a static method:

public class FactorialCalculator {
    public static int factorial(int number) {
        // Calculate factorial of number
    }
}

And you can call it this way:

int factorial = FactorialCalculator.factorial(5); // for the example

A static method is a method that is not associated with any instance of any class, & it can be accessed using the Classname.staticMethod( ) notation.

Upvotes: 10

user5425586
user5425586

Reputation:

You can either use a default constructor, which is just FactorialCalculator fc = new FactorialCalculator();. Easy as that. However, it looks like your teacher wants you to create a static method. Static methods are sort of like utilities of a class, instead of being a function of an object. So, in your case, you should make FactorialCalculator be more of a utility class instead of an object class. public static int factorial(int num) {} should do the trick. This way, you can just go FactorialCalculator.factorial(5) as you did in your example.

Hope this helps!

Upvotes: 1

user5618166
user5618166

Reputation:

It's Simple, if you make it Static, You will be able to call it from another class. Create it as a static method:

class FactorialCalculator {
    public static int factorial(int number) {
        ...YourCode...
    }
}

And you can call it this way:

int number = 10;
int f = FactorialCalculator.factorial(number);

Upvotes: 4

Kenney
Kenney

Reputation: 9093

If it is a static method, you would do FactorialCalculator.factorial(...).

Upvotes: 1

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