READING
CHAPTER 10
SECTION 5
"Two-Dimensional Arrays"

- table organized in columns
  - effective means for communicating many types of information
  - represented in Java with *two-dimensional arrays*
- so far, only one dimensional arrays
  - only one index
- declare a 2D array
  <type>[][] <identifier>;
  <type> <identifier>[][];
- create a 2D array
  <identifier> = new <type>[<size1>][<size2>];
- 2D array requires 2 indexes
  - one to specify the row
  - one to specify the column
- accessing an element of a 2D array
  - specify the row and column numbers as indexes
- accessing the length for each dimension
  - accessing the number of rows
    <identifier>.length
  - accessing the number of columns
    <identifier>[<row>].length
- no explicit 2D array structure in Java
  - faking it by using an array of arrays
  - shorthand for 
    - manually creating an array
    - manually creating a new array for each element of the first array
- subarray: array that is part of another array
  - don't all have to be the same length
- initialize an array of arrays at the time of declaration
  - nest the curly brace syntax
- no limit to the number of dimensions an array can have
  - arrays with dimensions greater than 2 rarely used in OO programming

Quick Check
1. int sum = 0, numElements = 0;
   for (int i = 0; i < payScaleTable.length; i++) {
       numElements += payScaleTable[i].length;
       for (int j = 0; j < payScaleTable[i].length; j++) {
           sum += payScaleTable[i][j];
       }
   }
   double average = (double) sum / numElements;
2. int biggest = table[0][0];
   for (int i = 0; i < table.length; i++) {
      for (int j = 0; j < table[i].length; j++) {
          if (table[i][j] > biggest) {
              biggest = table[i][j];
          }
      }
   }
3. 10
   5