Question

Using Java write a program that performs the following:

1. Define a class that contains an array of type int as a data member.
2. Define a constructor that creates an array of 1024 elements and assigns it to the class data member.
The constructor shall populate the elements with random numbers ranging in value from 1 to 1024.
3. Define and implement a search() method that take a parameter of type int and returns the index location if the value in the parameter is in the array, or -1 if it is not found.
4. Implement a main() method to exercise this class.

Answer 1

class ArrayExample{
    //Array of type int
    private int[] arr;

    //Constructor
    public ArrayExample(){
        //Create an array of 1024 elements
        arr = new int[1024];
        //Populate array with random numbers ranging in value from 1 to 1024
        for(int i = 0; i < 1024; i++){
            arr[i] = (int)(Math.random()*1024 + 1);
        }
    }

    public int search(int key){
        for(int i = 0; i < 1024; i++){
            //If key found then return the index
            if(arr[i] == key)
                return i;
        }
        //If key not found then return -1
        return -1;
    }
}

public class Main {
    // declaration of main method
    public static void main(String[] args) {
        ArrayExample ex = new ArrayExample();//Create an object of ArrayExample class
        //ex.search(5);
        System.out.println("ex.search(5) returned " + ex.search(5));
        System.out.println("ex.search(500) returned " + ex.search(500));
        System.out.println("ex.search(1024) returned " + ex.search(1024));
    }
}

SAMPLE OUTPUT:

ex.search (5) returned -l ex.search (500) returned 703 ex.search (1024) returned 433 Process finished with exit code 0