Question

Assignment Purpose

The purpose of this lab is to write a well commented java program that demonstrates the use of one dimensional arrays and methods.

Instructions

1. Write a method rotateArray that is passed to an array, x, of integers (minimum 7 numbers) and an integer rotation count, n. x is an array filled with randomly generated integers between 1 and 100.
2. The method creates a new array with the items of x moved forward by n Elements that are rotated off the array will appear at the end. Forward rotation means moving elements from right to left on paper. For example, suppose x contains the following items in sequence:

1 2 3 4 5 6 7 and the value of n = 3

3. Your program should first calculate the sum of numbers at even indexes (consider 0 as even) which in this case is 1 + 3 + 5 + 7 = 16, and then average of numbers at odd indexes which in this case is (2 + 4 + 6) / 3 = 4.
4. After that it should make a call to rotateArray with arguments as x and n.

Sample output

-----------------------Output Begins-------------------------

The randomly generated integers in array are: 1 2 3 4 5 6 7

Sum of numbers at even indexes = 16

Average of numbers at odd indexes = 4

Enter rotation count: 3

Calling rotateArray with rotation count as 3………

After 1^st rotation the array contents are         2 3 4 5 6 7 1

After 2^nd rotation the array contents are        3 4 5 6 7 1 2

After 3^rd rotation the array contents are        4 5 6 7 1 2 3

-----------------------End of Output----------------------------

So after rotating by 3, the elements in the new array will appear in this sequence:

4 5 6 7 1 2 3

Answer 1

import java.util.*;

public class Main{
        //Method to rotate array by one 
        static void RotatebyOne(int arr[], int n) 
    { 
        int i, temp; 
        // storing the first element in a temporary variable
        temp = arr[0]; 
        for (i = 0; i < n - 1; i++) 
            arr[i] = arr[i + 1]; 
        arr[i] = temp; 
    } 
        
        public static void rotateArray(int x[],int n) {
                //Rotating array one by one
                for(int i=0;i<n;++i) {
                        System.out.print("After " + (i+1) + " rotation the array contents are ");
                        RotatebyOne(x,x.length); 
                        //printing the array
                        for(int j=0;j<x.length;++j) {
                                System.out.print(x[j] + " ");
                        }
                        System.out.println();
                }
                
                System.out.print("So after rotating by " + n + ", the elements in the new array will appear in this sequence: ");
                //printing the array
                for(int i=0;i<x.length;++i) {
                        System.out.print(x[i] + " ");
                }
                System.out.println();   
        }

    public static void main(String[] args){
        
        Scanner input = new Scanner(System.in);
        
        int even=0,odd=0,c=0;
        int x[] = new int[7];
                for(int i=0;i<x.length;++i) {

                        //assigning random values to the array between 1 to 100
                        x[i] = (int) (Math.random() * (100 -1 + 1) + 1) ; 
                        // calculating sum of elements at even and odd places
                        if(i%2==0)
                                even += x[i];
                        else {
                                odd += x[i];
                                c++;
                        }               
                }
                
                System.out.print("The randomly generated integers in array are: ");
                for(int i=0;i<x.length;++i) {
                        System.out.print(x[i] + " ");
                }
                System.out.println("\nSum of numbers at even indexes = " + even);
                System.out.println("Average of numbers at odd indexes = " + (double)odd/c);
                System.out.print("Enter rotation count: ");

                //Reading input for n
                int n = input.nextInt();
                System.out.println("Calling rotateArray with rotation count as " + n + ".....");
                //Calling rotateArray method to rotate the array n times
                rotateArray(x,n);
      
    }

}

OUTPUT: