将数据从数组传输到不同的方法

Question

I am a beginner programmer in Java. Recently I started to learn how to use multiple methods in a single code. Right now, I am trying to create a code that takes data from a user-input array and uses it in a separate method in order to find the average of the inputed values (I plan on adding more to the code, which is why there's a String array of names, but right now I want to fully understand my current issue before making the code more complex). This is the code I have so far:

import java.util.*;

public class Example{


 public static double namesArray(){
    String[] names={"Employee A", "Employee B", "Employee C", "Employee D", "Employee E", "Employee F", "Employee G", "Employee H", "Employee I", "Employee J"};
 }


 public static double salesArray(){
    Scanner sc = new Scanner(System.in);
    double[] sales = new double[10];
    System.out.println("Enter the sales numbers, in dollars,  for each employee: ");
    for (int i = 0; i < sales.length; i++){
        sales[i] = sc.nextDouble();
    }

    System.out.println(Arrays.toString(names));
    System.out.println(Arrays.toString(sales));

    return sales;

 }
 public static double getAverage(){
    double sum=0;
    for (int i = 0; i < sales.length; i++){
    sum += i;
    }
    double average= sum/sales.length;
    return average;
 }
 public static void main(String[] args){
    namesArray();
    salesArray();
    average();
 }  
}

But when I compiled, I encountered these issues:

Example.java:19: error: cannot find symbol
            System.out.println(Arrays.toString(names));
                                               ^
symbol:   variable names
location: class LabFixing


Example.java:22: error: incompatible types: double[] cannot be converted to double
            return sales;
                   ^

Example.java:27: error: cannot find symbol
            for (int i = 0; i < sales.length; i++){
                                ^
symbol:   variable sales
location: class Example


Example.java:30: error: cannot find symbol
            double average= sum/sales.length;
                                ^
symbol:   variable sales
location: class Example


Example.java:36: error: cannot find symbol
            average();
            ^
symbol:   method average()
location: classExample

5 errors

I think the main problem I'm having is that I'm a bit unsure of how to pass arrays from one method to another. Any tips or advice would be greatly appreciated, thank you for your time.

Answer 1

There are a couple of problems in your code, the first and the most important being that your variables are local and not global, which means the variables are only recognized inside your local method and not by the entire class. So, you need to make them global. When you do this, you will not need the namesArray() method.

Once you make these variables global, your namesArray() and salesArray() doesn't need to return anything.

Next, the last method you invoke in your main() doesn't exist. Instead of average() try getArray().

Keeping that in mind, try

import java.util.*;

public class Example{
    static String[] names ={"Employee A", "Employee B", "Employee C", "Employee D", "Employee E", "Employee F", "Employee G", "Employee H", "Employee I", "Employee J"};
    static double[] sales = new double[10];


 public static void salesArray(){
    Scanner sc = new Scanner(System.in);
    System.out.println("Enter the sales numbers, in dollars,  for each employee: ");
    for (int i = 0; i < sales.length; i++){
        sales[i] = sc.nextDouble();
    }

    System.out.println(Arrays.toString(names));
    System.out.println(Arrays.toString(sales));

 }
 public static double getAverage(){
    double sum=0;
    for (int i = 0; i < sales.length; i++){
    sum += i;
    }
    double average= sum/sales.length;
    return average;
 }
 public static void main(String[] args){
    salesArray();
    System.out.println(getAverage());
 }  
}