Question

IN JAVA!

Lab 13 Problem 4 (name this Lab13_Problem4)

1. In main()construct a two-dimensional array named iVals using this statement (a 5-row, 4-column array):
   
   int iVals[][] = {{1,2,3,4}, {5,6,7,8}, {9,10,10,12}, {9,10,11,12}, {1,27,3,4}};
   
2. Also in main(), declare a Boolean variable bDups which will be used to store the return value of the method below.
3. Write a method fvDisplay() to display the array, allocating 6 horizontal spaces for each column (or just reuse the method from the previous problem).
4. Write a method fbDupRows() which checks each row against the other rows in the matrix and indicates whether there are duplicates.
5. A duplicate row is identified when you compare a row against all the rows below it, column by column. If all the values in each column are the same between each row, then you have a duplicate row. Hint: you need a duplicate counter, which you need to reset to 0 for each row.
6. When your method completes its examination of the array, return a value of true if any rows are duplicates, false if there are no duplicates.
7. In main(), examine the return value and display either:
   
   Duplicate Rows Found
   
   or
   
   No Duplicate Rows Found
   
8. Test your algorithm by changing the values in the array from the original in step 1 above (which has no duplicate rows).
   1. Make two adjacent rows identical, run the app, and verify it returns duplicates.
   2. Then try two duplicate rows, separated by a non-duplicated row; make sure that also works.

Answer 1

SHORT SUMMARY:

• Implemented the main() function as per the requirements provided.
• Provided the source code with three different test cases as mentioned in the question.
• Given the sample output and screenshot of the source code.

SOURCE CODE:

public class Duplicate2DArray {

    public static void main(String[] args) {

        // TEST CASE 1 - No duplicates

        System.out.println("\nTEST CASE 1");

        int iVals[][] = {{1, 2, 3, 4}, {5, 6, 7, 8}, {9, 10, 10, 12}, {9, 10, 11, 12}, {1, 27, 3, 4}};

        fvDisplay(iVals);

        boolean bDups = fbDupRows(iVals);

        if (bDups) {

            System.out.println("\nDuplicate Rows Found");

        } else {

            System.out.println("\nNo Duplicate Rows Found");

        }

       

        // TEST CASE 2 - Adjacent Rows identical - 1st and 2nd Row duplicate value

        System.out.println("\nTEST CASE 2");

        int iVals1[][] = {{1, 2, 3, 4}, {1, 2, 3, 4}, {9, 10, 10, 12}, {9, 10, 11, 12}, {1, 27, 3, 4}};

        boolean bDups1 = fbDupRows(iVals1);

        fvDisplay(iVals1);

        if (bDups1) {

            System.out.println("\nDuplicate Rows Found");

        } else {

            System.out.println("\nNo Duplicate Rows Found");

        }

       

        // TEST CASE 3 - 2nd and 4th rows same value

        System.out.println("\nTEST CASE 3");

        int iVals2[][] = {{1, 2, 3, 4}, {5, 6,7, 8}, {9, 10, 10, 12}, {5, 6, 7, 8}, {1, 27, 3, 4}};

        boolean bDups2 = fbDupRows(iVals2);

        fvDisplay(iVals2);

        if (bDups2) {

            System.out.println("\nDuplicate Rows Found");

        } else {

            System.out.println("\nNo Duplicate Rows Found");

        }

    }

    // Display array with 6 horizontal space

    private static void fvDisplay(int[][] iVals) {

        // iterating through rows

        for (int row = 0; row < iVals.length; row++) {

            // iterating through columns

            for (int column = 0; column < iVals[row].length; column++) {

                // Display array values with horizontal space of 6

                System.out.printf("%6d", iVals[row][column]);

            }

            System.out.println("");

        }

    }

    // checks whether there are duplicate rows

    private static boolean fbDupRows(int[][] iVals) {

        // iterating through rows

        for (int row1 = 0; row1 < iVals.length; row1++) {

            // iterating from next rows

            for (int row2 = row1 + 1; row2 < iVals.length; row2++) {

                // counter variable

                int dupCount = 0;

                // iterating through the column

                for (int column = 0; column < iVals[row1].length; column++) {

                    // check the values are equal

                    if (iVals[row1][column] == iVals[row2][column]) {

                        // increment the counter variable

                        dupCount++;

                    }

                }

                // if the counter variable value equals to column duplicate found

                if (dupCount == iVals[row1].length) {

                    return true;

                }

            }

        }

        // when no duplicates found

        return false;

    }

}

CODE SCREENSHOT:

SAMPLE OUTPUT:

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