2D array operations

The problem

Write a program that creates a two-dimensional array initialized with test data. Use any primitive data type you wish. The program should have the following methods.

getTotal - This method should accept a two-dimensional array as its argument and return the total of all the values in the array.
getAverage - This method should accept a two-dimensional array as its argument and return the average of all the values in the array.
getRowTotal. - This method should accept a two-dimensional array as its first argument and an integer as its second argument. The second argument should be the subscript of a row in the array. The method should return the total of the values in the specified row.
getColumnTotal - This method should accept a two-dimensional array as its First argument and an integer as its second argument. The second argument should be the subscript of a column in the array. The method should return the total of the values in the specified column.
getHighestInRow - This method should accept a two-dimensional array as its First argument and an integer as its second argument. The second argument should be the subscript of a row in the array. The method should return the Highest values in the specified row in the array.
getLowestInRow - This method should accept a two-dimensional array as its First argument and an integer as its second argument. The second argument should be the subscript of a row in the array. The method should return the lowest values in the specified row in the array.

Demonstrate each of the methods in this program.

While we have shown the requirements of the question asked above, each of the methods below translates into a defined behavior for a one dimensional array. Breaking it down further instead of creating methods you could use the following passing in the array you wish to perform the calculation on:

Method name	Behavior
getAverage	Find average of elements in array
getRowTotal/getTotal	Add all elements of array to find sum
getHighestInRow	Find highest value in array
getLowestInRow	Find lowest value in array

Breaking it down

public static double getTotal(double[][] array) {
    double total = 0;

    for (int row = 0; row < array.length; row++) {
        for (int col = 0; col < array[row].length; col++) {
            total += array[row][col];
        }
    }

    return total;
}

public static double getAverage(double[][] array) {
    return getTotal(array) / getElementCount(array);
}

public static double getRowTotal(double[][] array, int row) {
    double total = 0;

    for (int col = 0; col < array[row].length; col++) {
        total += array[row][col];
    }

    return total;
}

public static double getColumnTotal(double[][] array, int col) {
    double total = 0;

    for (int row = 0; row < array.length; row++) {
        total += array[row][col];
    }

    return total;
}

public static double getHighestInRow(double[][] array, int row) {
    double highest = array[row][0];

    for (int col = 1; col < array[row].length; col++) {
        if (array[row][col] > highest) {
            highest = array[row][col];
        }
    }
    return highest;
}

public static double getLowestInRow(double[][] array, int row) {
    double lowest = array[row][0];

    for (int col = 1; col < array[row].length; col++) {
        if (array[row][col] < lowest) {
            lowest = array[row][col];
        }
    }
    return lowest;
}

public static int getElementCount(double[][] array) {
    int count = 0;

    for (int row = 0; row < array.length; row++) {
        count += array[row].length;
    }
    return count;
}

public static void main(String[] args) {

    double[][] studentTestScores = { { 65.5, 54.43, 23.54, 99.5 },
            { 33.4, 22.55, 54.66, 11.12 } };

    // Process the double array.
    System.out.println("Total : " + getTotal(studentTestScores));
    System.out.println("Average : " + getAverage(studentTestScores));

    System.out.println("Total of row 0 : "
            + getRowTotal(studentTestScores, 0));
    System.out.println("Total of row 1 : "
            + getRowTotal(studentTestScores, 1));

    System.out.println("Total of col 0 : "
            + getColumnTotal(studentTestScores, 0));
    System.out.println("Total of col 1 : "
            + getColumnTotal(studentTestScores, 2));

    System.out.println("Highest in row 0 : "
            + getHighestInRow(studentTestScores, 0));
    System.out.println("Highest in row 1 : "
            + getHighestInRow(studentTestScores, 1));

    System.out.println("Lowest in row 0 : "
            + getLowestInRow(studentTestScores, 0));
    System.out.println("Lowest in row 1 : "
            + getLowestInRow(studentTestScores, 1));

}

Output

Total : 364.70000000000005
Average : 45.587500000000006
Total of row 0 : 242.97
Total of row 1 : 121.73
Total of col 0 : 98.9
Total of col 1 : 76.98
Highest in row 0 : 99.5
Highest in row 1 : 54.66
Lowest in row 0 : 23.54
Lowest in row 1 : 11.12

Level Up

Write a Junit unit test to validate the logic if each method behaves as you expect
Instead of passing a two-dimensional array and a subscript, refactor to use the appropriate min, max, sum and count methods.
Fix all output to be two decimal places by writing a method that accepts a double and returns a formatted string.