Call method with defined vector elements parameter

Question

Good night!

I have created a method that calculates the elements of a vector and makes the general mean, but I am not able to call it in the main method. PS: I am a beginner.

Thanks for your help!

package proj04;

public class media {

    private static double mediatotal;
    private static double[] notasAlunos = {10, 5, 7, 8, 6, 8, 10, 9, 7, 6, 7, 6, 8, 4, 6};

    public static double getMediatotal() {
        return mediatotal;
    }
    public static void setMediatotal(double mediatotal) {
        media.mediatotal = mediatotal;
    }

        public static double mediat(double notasAlunos[]) {

            double soma = 0;
            for (int i = 0; i < 15; i++) {
                soma = (soma + notasAlunos[i]) / 15;
                mediatotal = soma;
            }
            return soma;
        }               
    }

package proj04;

public class exe4main {

    public static void main(String[] args) {
        double mediavar;
        media mediaturma = new media();

        System.out.println( mediaturma.getMediatotal());            
    }    
}

Answer 1

I did not find the error in your code, but I leave some tips.

Usually class name starts with uppercase letter.

The functions and variables of your class media are all static then you don’t need to create an instance of it new media() you can access directly by the Ex class. media.getMediatotal().

In the main you are printing on the return of getMediatotal which at present is still null.

You defined private static double[] notasAlunos as private then you won’t be able to access it outside the class media and apparently you want to pass it on to the function mediat, options:

1. Change the private for public or leave without either of the two, without either of the two will work by being in the same package.

2. Not receive notasAlunos per parameter in function mediat access from within it.

I made some changes to your code and put it formatted to run on Ideone see him running

class Exe4main
{
    public static void main (String[] args) // throws java.lang.Exception
    {
        double mediavar;

        Media.mediat( Media.notasAlunos );
        System.out.println( Media.getMediatotal() ); 
    }
}

class Media {

    private static double mediatotal;
    public static double[] notasAlunos = {10, 5, 7, 8, 6, 8, 10, 9, 7, 6, 7, 6, 8, 4, 6};

    public static double getMediatotal() {
        return mediatotal;
    }
    public static void setMediatotal(double mediatotal) {
        Media.mediatotal = mediatotal;
    }

    public static double mediat(double notasAlunos[]) {

        double soma = 0;
        for (int i = 0; i < 15; i++) {
            soma = (soma + notasAlunos[i]) / 15;
            mediatotal = soma;
        }
        return soma;
    }               
}

---

A way to access or change a variable private would create methods get and set 'public' for this variable, that is, the same way you did for the variable mediatotal, see another example below

class Media{

    private static double[] minhaVar;

    public static void setMinhaVar( double[] novoValor ){

        minhaVar = novoValor;

    }

    public static double[] getMinhaVar( ) {

        return minhaVar;

    }
}