Fill an array with random numbers

Question

I need to create an array using a constructor, add a method to print the array as a sequence and a method to fill the array with random numbers of the type double.

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Answer 1

If the randomness is controlled like this there can always generate any number of data points of a given range. If the random method in java is only used, we cannot guarantee that all the numbers will be unique.

package edu.iu.common;

import java.util.ArrayList;
import java.util.Random;

public class RandomCentroidLocator {

public static void main(String [] args){
	
	int min =0;
	int max = 10;
	int numCentroids = 10;
	ArrayList values = randomCentroids(min, max, numCentroids);	
	for(Integer i : values){
		System.out.print(i+" ");
	}
	
}

private static boolean unique(ArrayList arr, int num, int numCentroids) {

	boolean status = true;
	int count=0;
	for(Integer i : arr){
		if(i==num){
			count++;
		}
	}
	if(count==1){
		status = true;
	}else if(count>1){
		status =false;
	}
	

	return status;
}

// generate random centroid Ids -> these Ids can be used to retrieve data
// from the data Points generated
// simply we are picking up random items from the data points
// in this case all the random numbers are unique
// it provides the necessary number of unique and random centroids
private static ArrayList randomCentroids(int min, int max, int numCentroids) {

	Random random = new Random();
	ArrayList values = new ArrayList();
	int num = -1;
	int count = 0;
	do {
		num = random.nextInt(max - min + 1) + min;
		values.add(num);
		int index =values.size()-1;
		if(unique(values, num, numCentroids)){				
			count++;
		}else{
			values.remove(index);
		}
		
	} while (!( count == numCentroids));

	return values;

}

}