Calculator and using arrays

Question

I am trying to get this working so when a user types in numbers it in turn outputs the max, min, sum and avg of those numbers. The first number is the amount of numbers going to be entered. I am supposed to call methods to do each calculation and use the main method to print. When I go to enter something in into just prints out 0.00 and not the actual min, max, sum and avg. It prints out 0.00 equal to the first number typed in which it shouldn't do. Any help would be appreciated.

Sample Input
   5 1.0 2.0 3.0 4.0 5.0

Sample Output
   15.00 3.00 1.00 5.00

My current code

import java.util.Arrays;
import java.util.Scanner;

public class ManyNumbers {

public static void main(String args[]) {

    double i,n;
     Scanner input = new Scanner(System.in);
     while(input.hasNext()){
     n=input.nextInt();
     double a[] = new double [(int) n];

     for(i=0;i<n;i++){
       a[(int) i] = input.nextDouble();
       double max1 = max (a);
       double min1 = min (a);
       double sum1 = sum (a);
       double avg= sum1/n;
       System.out.printf("%10.2f",min1, max1, sum1, avg);}
     }
}
        private static double sum(double[] array){
        double sum = 0;
        for (double e : a) sum += e;
        return sum;}

        private static double min(double[] a){
        Arrays.sort(a);
        double min =a[0];
        return min;}

        private static double max(double[] a){
        Arrays.sort(a);
        double max= a[a.length -1];{
        return max;}
    }
}

Answer 1

This is the final code that worked with the formatting that was required of it.

import java.util.Arrays;
import java.util.Scanner;

public class ManyNumbers {
public static void main(String[] args) {
    Scanner in = new Scanner(System.in);
    while(in.hasNext()){
    int arraysize = in.nextInt();
    Double[] array = new Double[arraysize];
    for (int i = 0; i < arraysize; i++) {
        array[i] = in.nextDouble();
    }
    double sum1 = sum(array);
    double max1 = max(array);
    double min1 = min(array);
    double avg= sum1/arraysize;
    System.out.printf("%10.2f",sum1);
    System.out.printf("%10.2f",avg);
    System.out.printf("%10.2f",min1);
    System.out.printf("%10.2f",max1);
    System.out.println();}
}

private static double sum(Double[] array) {
    double sum = 0;
    double i = 0; // N is zero
    Double a[] = new Double[array.length];
    a = array;

    for (double e : a)
        sum += e;
    return sum;
}

private static double min(Double[] array) {
    Double a[] = new Double[array.length];
    a = array;
    Arrays.sort(a);
    double min = a[0];
    return min;
}

private static double max(Double[] array) {
    Arrays.sort(array);
    double max = array[array.length - 1];
    return max;
}
}

Answer 2

Here is the fully corrected version: So I fixed your input so that it could be varied and fixed you methods as well.

import java.util.Arrays;
import java.util.Scanner;

public class ManyNumbers {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int arraysize = in.nextInt();
        Double[] array = new Double[arraysize];
        for (int i = 0; i < arraysize; i++) {
            array[i] = in.nextDouble();
        }
        System.out.println(sum(array) + " " + min(array) + " " + max(array));
    }

    private static double sum(Double[] array) {
        double sum = 0;
        double i = 0;
        Double a[] = new Double[array.length];
        a = array;

        for (double e : a)
            sum += e;
        return sum;
    }

    private static double min(Double[] array) {
        Double a[] = new Double[array.length];
        a = array;
        Arrays.sort(a);
        double min = a[0];
        return min;
    }

    private static double max(Double[] array) {
        Arrays.sort(array);
        double max = array[array.length - 1];
        return max;
    }
}

Answer 3

I tried to read that, but the indentation is really weird, tried to indent it:

EDIT: Ok so I am done indenting, the problem seems to be that you set N to 0 then create an array of size n (which is 0). You've done this in 3 methods.

import java.util.Arrays;
import java.util.Scanner; 
public class ManyNumbers {
   public static void main(String args[]) {

       double i,n; 
       Scanner input = new Scanner(System.in);
       while(input.hasNext()){
           n=input.nextInt();
           double a[] = new double [(int) n];

           for(i=0;i<n;i++){
               a[(int) i] = input.nextDouble();
               double max1 = max (a);
               double min1 = min (a);
               double sum1 = sum (a);
               double avg= sum1/n;
               System.out.printf("%10.2f",min1, max1, sum1, avg);
          }
       }
   }
   private static double sum(double[] array){
       double sum = 0;
       double i,n = 0; //N is zero
       double a[] = new double [(int) n];//Creating an array of size n(0)


       for (double e : a)
           sum += e;
       return sum;
   }

   private static double min(double[] array){
       double i,n = 0; //N is zero
       double a[] = new double [(int) n]; //Creating array of size N
       Arrays.sort(a);
       double min =a[0];
       return min;
   }

   private static double max(double[] array){
       double i,n = 0; // N is zero
       double a[] = new double [(int) n]; //Creating array of size 0
       Arrays.sort(a);
       double max= a[a.length -1];

       {//Why?
           return max;
       }
   }
}

EDIT2: I think i may have found your problem. It seems like you thought nfrom main() was global scope. You then defined another local variable for each method with the same name, which made you think it was the same variable, which it wasnt. I would have posted the right way to do it but i dont have the time, i'm sorry.

Answer 4

There are definitely a number of issues with the code but it seems to me that the very first initialization of the double array a, should not be declared every time the loop runs. You're not adding all the user input to a single array rather creating new arrays every time the user enters input. You'd have to write code to ask how many numbers the user is inputing or hardcode it before you declare the double array. Something like this:

Scanner input = new Scanner(System.in);
System.out.println("Please enter the number of doubles to add to the array");
n=input.nextInt();
double a[] = new double [(int)n];

That will only take care of your first issue. I would also use a for loop with a counter to add the doubles to the array after that. The methods need work too but this will hopefully give you a start. Good luck!