Question

JAVA, Please do as asked and show solution/code clearly and let code ready to be copied: complete the remaining exercises as methods within that class

Write a Java method that: - takes as input parameter a 2D array of numbers, with R rows and C columns - and fills the array following the next rule (for R = 3 and C = 5): [[1, 2, 3, 4, 5] [1, 2, 3, 4, 5] [1, 2, 3, 4, 5]] - print array within method - void return Test it by creating an empty 2D array in main and calling this method on that array.

Write a Java method that: - takes as input a 2D array of numbers - and returns the number of even elements in the array - e.g. If the input 2D array is [[1, 2, 3] [4, 5, 5] [2, 7, 1]], the output should be 3 (because 2, 4, 2 are even) Test your method by calling it from the main method using a user defined array. Print the number of even elements on screen.

Write a Java method that: Method name: swapArray - takes as input a 2D array of numbers and 2 row indices R1 and R2 - and swaps the row R1 with the row R2 from the array - e.g. If the input 2D array is 1 1 1 1 2 2 2 2 3 3 3 3 4 4 4 4 - and R1 = 1 and R2=3, then the output should be: 1 1 1 1 4 4 4 4 3 3 3 3 2 2 2 2 Test your method by calling it from the main method using a user defined 2D array. Print the array content before and after the method call.

Answer 1

public class ArrayTest {

   public static void fillArray(int arr[][], int r, int c) {
       for (int i = 0; i < r; i++) {
           for (int j = 0; j < c; j++)
               arr[i][j] = j + 1;
       }
   }

   public static void printArray(int arr[][], int r, int c) {
       for (int i = 0; i < r; i++) {
           for (int j = 0; j < c; j++)
               System.out.print(arr[i][j]+" ");
           System.out.println();
       }
   }

   public static int evenCount(int arr[][], int r, int c) {
       int count = 0;
       for (int i = 0; i < r; i++) {
           for (int j = 0; j < c; j++)
               if (arr[i][j] % 2 == 0)
                   count++;
       }
       return count;
   }

   public static void swapRow(int arr[][], int r1, int r2) {
       int count = 0;
       for (int i = 0; i < arr[r1].length; i++) {
           int temp = arr[r1][i];
           arr[r1][i] = arr[r2][i];
           arr[r2][i] = temp;
       }
   }

   public static void main(String[] args) {
       int arr[][]=new int[3][5];
       fillArray(arr, 3, 5);
       printArray(arr, 3, 5);
       System.out.println("Even numbers count "+evenCount(arr, 3, 5));
   }
}