CODEWITHSUNDEEP
javaarraysloops
user2383438
user2383438

Reputation: 11

How to organize random values in order?

I have a program here that allows an user to input a number (n) and the program outputs 'n' random numbers. I need to create a loop that organizes these random values from lowest to largest, but I am unsure how to go about doing that, any ideas? Thanks,

// takes inputted value to "randomize" numbers too
int amtOfNumbers = Integer.parseInt(amtOfNumbersField.getText()); 
int[] random = new int[amtOfNumbers-1]; // 1 prevents array from including 0
Random r = new Random(); //for random values

// Insert random numbers into the array
for (int i = 0; i < random.length; i++) {
    random[i] = r.nextInt(100) + 1;
}

// Output random numbers
for (int i = 0; i < random.length; i++) {
    itsATextArea.append(random[i] + "\n");
}

I stored the information (random n values) in the array so I can call them out later.

Upvotes: 0

Views: 1999

Answers (3)

75inchpianist
75inchpianist

Reputation: 4102

You can put them into an arraylist and define your own Comparator to sort them. For example.

int amtOfNumbers = Integer.parseInt("10");

ArrayList<Integer> randomList= new ArrayList<Integer>();
Random r = new Random(); //for random values

// Insert random numbers into the set
for (int i = 0; i < amtOfNumbers; i++) {
    randomList.add(r.nextInt(100) + 1);
}

//Now sort it however way you want
Collections.sort(randomList, new MyCustomComparator());

All you need is to define a new comparator

public class MyCustomComparator implements Comparator<Integer>(){

   public int compare(Integer o1, Integer o2){
      //say I want descending order
      return -1* o1.compare(o2);
   }
}

but you can sort it however you want. Just make sure it returns -1 if you want to consider the current value o1, less than o2, return 0 if they are to be considered equal, or 1 if greater than based on your if statement conditions.

Upvotes: 1

Ravi K Thapliyal
Ravi K Thapliyal

Reputation: 51711

Use a data structure like TreeSet to keep your data in sorted order automatically.

int amtOfNumbers = Integer.parseInt("10");

TreeSet<Integer> randomSet = new TreeSet<Integer>();
Random r = new Random(); //for random values

// Insert random numbers into the set
for (int i = 0; i < amtOfNumbers; i++) {
    randomSet.add(r.nextInt(100) + 1);
}

// Output in Ascending order
for (Integer i: randomSet) {
   System.out.println(i);
}

To output the numbers in descending order

// Descending order
for (Integer i: randomSet.descendingSet()) {
    System.out.println(i);
}

Upvotes: 3

James Montagne
James Montagne

Reputation: 78650

Java has built-in sort capability:

// Insert random numbers into the array
for (int i = 0; i < random.length; i++) {
    random[i] = r.nextInt(100) + 1;
}

Arrays.sort(random);

// Output random numbers
for (int i = 0; i < random.length; i++) {
    itsATextArea.append(random[i] + "\n");
}

Upvotes: 2

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