Question

put everything together in an object-oriented manner!

1. create a class named PositiveNumberStatistics that has the following:

   • A private double 1D array instance variable named numbers.

   • A constructor that takes one parameter, a 1D double array. The constructor should throw an IllegalArgumentException with the message "Array length of zero" if the parameter has a length of 0. If the exception is not thrown, the constructor should create the numbers array and copy every element from the parameter into the numbers instance variable. However, if any of the elements are less than or equal to zero, the constructor should throw a NumberFormatException with the message "Non-positive value at index X" where X is the first index at which a non-positive value occurs.

   • A method named average that does not take any parameters and returns a double. The method should return the average of the numbers in the instance variable numbers. Note that you do not need to worry about whether the numbers instance variable has been created in this method because this method will only be usable if the constructor does not throw an exception.

Answer 1

Here is the java code :

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import java.io.*;
import java.util.*;
class PositiveNumberStatistics
{
private double numbers[];
public PositiveNumberStatistics(double argument[])
{
int len = argument.length;
   if(len==0)
   {
    throw new IllegalArgumentException("Array Length of zero");
   }
   else
   {
    numbers = new double[len];
    for(int i=0;i<len;i++)
    {
     if(argument[i]<=0) {
      throw new NumberFormatException("Non-positive value at index "+ i);
     }
     else
      numbers[i]=argument[i];
    }
   }   
}
public double average()
{
int len=numbers.length;
double avg=0;
for(int i=0;i<len;i++)
    avg = avg+numbers[i];
    avg = avg/len;
   return avg;
}
   
public static void main(String args[])
{
   Scanner s = new Scanner(System.in);
   int n=s.nextInt();
   double arg[] = new double[n];
   for(int i=0;i<n;i++)
    arg[i] = s.nextDouble();
PositiveNumberStatistics pns = new PositiveNumberStatistics(arg);
   double res = pns.average();
   System.out.println(res);
}
}
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