public class MultidimensionalArraysExercises02{

    /* Two-dimensional Arrays
      2. Write a method that takes a two-dimensional array as a parameter (and
      no other parameters). Have the method populate each value in the array.
      Start with 0.0 in the first index, then 0.001 in the second, etc.
      What should the return value be? Write some code to test your method.
    */
    /**
     * Simulates data with 0.000 in the first element and 0.001 in the second, etc.
     * @param array A rectangular or ragged array
     */
    public static void populate( double[][] array ){
        double value = 0.0;
        double step = 0.001;
        int numRows = array.length;
        for( int rowI = 0; rowI < numRows; ++rowI){
            int numCols = array[rowI].length;
            for( int colI = 0; colI < numCols; ++colI){
                array[rowI][colI] = value;
                value += step;
            }
        }
    }

    /* Two-dimensional Arrays
      3a. Write a method that takes a two-dimensional array as a parameter (and
      no other parameters). Have the method return the total of all of the
      values in the array. Write some code to test your method. (If you use the
      method described above to populate each value in the rainfall array, then
      you should get a total of approximately 66.43. Note, if you're getting a
      total of 69.006, then you're probably using a rectangular array instead of
      a ragged or jagged array.)
    */

    /**
     * Calculates the total of all of the values
     * @param array A rectangular or ragged array
     * @return The sum of all of the values in array
     */
    public static double total( double[][] array ){
        double total = 0.0;
        int numRows = array.length;
        for( int rowI = 0; rowI < numRows; ++rowI){
            int numCols = array[rowI].length;
            for( int colI = 0; colI < numCols; ++colI){
                total += array[rowI][colI];
            }
        }

        return total;
    }
    public static double total2( double[][] array ){
        double total = 0.0;
        int numRows = array.length;
        for( int rowI = 0; rowI < numRows; ++rowI){
            double[] cols = array[rowI]; // simplify the following code by creating a reference to the column array
            int numCols = cols.length;
            for( int colI = 0; colI < numCols; ++colI){
                total += cols[colI];
            }
        }

        return total;
    }

    public static void main( String[] args ){

        /* Two-dimensional Arrays
        1. Declare a two-dimensional array that can hold the amount of rainfall
        for everyday in a year. The first index should be the month and the
        second index the day of the month.
        */
        double[][] rainfallRectangular = new double[12][31];
        double[][] rainfall = new double[12][]; // ragged array
        int monthI = 0;
        rainfall[monthI++] = new double[31]; // January
        rainfall[monthI++] = new double[28]; // February
        rainfall[monthI++] = new double[31]; // March
        rainfall[monthI++] = new double[30]; // April
        rainfall[monthI++] = new double[31]; // May
        rainfall[monthI++] = new double[30]; // June
        rainfall[monthI++] = new double[31]; // July
        rainfall[monthI++] = new double[31]; // August
        rainfall[monthI++] = new double[30]; // September
        rainfall[monthI++] = new double[31]; // October
        rainfall[monthI++] = new double[30]; // November
        rainfall[monthI++] = new double[31]; // December

        populate( rainfall );


        System.out.println( "Last rainfall amount: " + rainfall[ 11 ][ 30 ] ); // December 31st

        /* Two-dimensional Arrays
          3b. Write some code to test your method.
          (If you use the method described above to populate each value in the
          rainfall array, then you should get a total of approximately 66.43.
          Note, if you're getting a total of 69.006, then you're probably using
          a rectangular array instead of a ragged or jagged array.)
        */

        System.out.println( "Total rainfall: " + total( rainfall ) );



        /* Multidimensional Arrays
          1. Declare a multi-dimensional array that can hold the amount of
          rainfall for everyday in a year for 100 years. The first index should
          be the year, the second index the month and the third index the day of
          the month. Will the methods described above work in this three-
          dimensional array? Discuss with someone else why or why not.
        */
        double[][][] rainfall3DRectangular = new double[100][12][31];
        double[][][] rainfall3D = new double[100][12][];

        for(int yearI = 0; yearI < rainfall3D.length; ++yearI){
            monthI = 0;
            rainfall3D[yearI][monthI++] = new double[31]; // January
            rainfall3D[yearI][monthI++] = new double[28]; // February
            rainfall3D[yearI][monthI++] = new double[31]; // March
            rainfall3D[yearI][monthI++] = new double[30]; // April
            rainfall3D[yearI][monthI++] = new double[31]; // May
            rainfall3D[yearI][monthI++] = new double[30]; // June
            rainfall3D[yearI][monthI++] = new double[31]; // July
            rainfall3D[yearI][monthI++] = new double[31]; // August
            rainfall3D[yearI][monthI++] = new double[30]; // September
            rainfall3D[yearI][monthI++] = new double[31]; // October
            rainfall3D[yearI][monthI++] = new double[30]; // November
            rainfall3D[yearI][monthI++] = new double[31]; // December
        }

        for(int yearI = 0; yearI < rainfall3D.length; ++yearI){
            populate( rainfall3D[yearI] );
        }
    }
}