Section 8: Using Variables: Arrays and Strings 130
We need to use a two-dimensional array to store the values in the following table:
 
Number Square Square root Factorial
  1
2
3
  1
4
9
1
1.41421356237
1.73205080757 		 
  1
2
6
 
This table contains 3 rows and 4 columns for a total of 12 values.
If subscript numbering begins at 0, the elements are identified as follows:
 
  D(0,0)=1
D(1,0)=2
D(2,0)=3
  D(0,1)=1
D(1,1)=4
D(2,1)=9
  D(0,2)=1
D(1,2)=1.41421356237
D(2,2)=1.73205080757
  D(0,3)=1
D(1.3)=2
D(2.3)=6
 
  Array D  
 
Subscript 0 1 2 3
0
1
2
1
2
3
1
4
9
  1
1.41421356237
1.73205080757
1
2
6
 
Each element in array D is specified by its location in the array with two subscripts, separated by a comma, and enclosed within parentheses. The first subscript designates the ‘‘row’’ in the array; the second subscript designates the ‘‘column’’.
If numbering of the subscript begins with 1, array D would be represented:
 
Subscript 1 2 3 4
1
2
3
1
2
3
1
4
9
  1
1.41421356237
1.73205080757
1
2
6
 
Thus, 9 would be represented as D(3,2); 6 would be represented as D(3,4).
Array names are the same as simple variable names; an array name may be a letter from A through Z, or a letter immediately followed by a digit from 0 through 9. But whenever an array is specified, it must be followed by subscripts enclosed within parentheses, otherwise it specifies a simple variable. The range of each subscript is an integer from 0 through 32767, but the maximum array size is determined by available memory. A non-integer subscript is rounded to the nearest integer if it is within the dimensioned range of subscripts.
Arrays are extremely convenient for handling large groups of data within a program because a group of different values are known under the same name. The different values (or elements of the array) are distinguished in name by subscripts to the array name.
An array name followed by a single subscript enclosed within parentheses specifies a one-dimensional array or an element of that array. An array name followed by two subscripts separated by a comma, both enclosed within parentheses, specifies a two-dimensional array or an element of that array. (No more than two subscripts are allowed.) Whether the array name is understood as the whole array or as a specific element depends on the type of statement that is used. Declaration statements refer to the whole array, executable statements usually refer to an array element.