CODEWITHSUNDEEP
javaobject
Nebular
Nebular

Reputation: 123

simple objects and methods

Program is to add and average and list amount of times the "addNumber" method is called.

I can make the Amount work, but nothing else

public class Main {
    public static void main(String[] args) {
        NumberStatistics stats = new NumberStatistics();
        stats.addNumber(3);
        stats.addNumber(5);
        stats.addNumber(1);
        stats.addNumber(2);
        System.out.println("Amount: " + stats.amountOfNumbers());
        System.out.println("sum: " + stats.sum());
        System.out.println("average: " + stats.average());
    }

public class NumberStatistics {
    private int amountOfNumbers;
    private int addNumber; 
    private double average; 
    private int sum; 

public NumberStatistics() {
    this.amountOfNumbers=amountOfNumbers; 
    this.average=0; 
    this.sum=0;
}

public void addNumber(int number) {
    number=addNumber; 
    addNumber++; 
    // code here
}
public int amountOfNumbers() {
    return addNumber; 
    // code , here
}
public int sum() {
    return this.addNumber++; 
}

public double average() {
    return sum() / addNumber; 
}

My incorrect output:

Amount: 4 sum: 4 average: 0.0

Upvotes: 3

Views: 372

Answers (2)

theVoid
theVoid

Reputation: 743

Ok lets start with the constructor.

public NumberStatistics() {
this.amountOfNumbers=amountOfNumbers; 
this.average=0; 
this.sum=0;}

Here when you create an object you initialize average and sum to 0 but this.amountOfNumbers=amountOfNumbers; has no particular effect. To sum up what i think you wanted to do is something like this:

public NumberStatistics()
{
   this.average = 0;//this keyword here is not needed but i used it since you did too
   this.sum = 0;
   this.amountOfNumbers = 0;
}

Then we go to this block of code here:

public void addNumber(int number) {
  number=addNumber; 
  addNumber++; 
}

Ok, this line makes no sense since you are setting the parameter equal to the addNumber variable which is something that does not help you at all, what i think you wanted to do here is the following:

public void addNumber(int number) {
   sum += number;//same as sum = sum + number; 
   amountOfNumbers++;//same as amountOfNumbers = amountOfNumbers +1;
}

Then you need a method that returns the average like this:

public double average() {
  return  average = sum / amountOfNumbers; //i use the average variable only because you did, 
  //the most efficient way here is just to return sum / amountOfNumbers
}

Finally, the last two methods that i think you were trying to create are these:

public int amountOfNumbers() {
    return amountOfNumbers; 
}

public int sum() {
  return sum; 
}

This is my first post ever so i hope that it helps.

Upvotes: 2

Elliott Frisch
Elliott Frisch

Reputation: 201439

In NumberStatistics, you only need the count and a sum. You add to the sum with addNumber (and increment the count). Something like,

public class NumberStatistics {
    private int count = 0;
    private int sum = 0;

    public void addNumber(int number) {
        this.sum += number;
        count++;
    }

    public int getCount() {
        return count;
    }

    public int sum() {
        return sum;
    }

    public double average() {
        return sum() / (double) getCount();
    }
}

Upvotes: 1

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