1. A table is a useful way to capture a discrete function. Days Per Month MonthLength 1) Jan 31 2) Feb 28 3) Mar 31... 12) Dec 31 Cost Per Burger QuantityItem Cost 0 $0.00 1 $1.50 2 $1.40 3 $1.35 4 or more $1.30 Mileage Between Cities AlbanyAtlanta BoiseMiami Albany 0 1025 2527 1441 Atlanta 1025 0 2214 653 Boise 2527 2214 0 2861 Miami 1441 653 2861 0 Decoding Table Letter A B C D E F G H I J K L M N O P Q R S T U V W X Y Z Cypher X C B H T Z I D G Y Q P N M U L K W V E O S R A J F

2. Often an array is an efficient way to store tabular information. Cost Per Burger QuantityItem Cost 0 $0.00 1 $1.50 2 $1.40 3 $1.35 4 or more $1.30 double[] burgerCost = {0.0, 1.5, 1.4, 1.35, 1.3}; The following code displays the cost for quantity burgers (assuming a non-negative quantity). if (quantity < burgerCost.length) { System.out.println( quantity * burgerCost[quantity] ); } else { System.out.println( quantity * burgerCost[burgerCost.length-1] ); } This is an example of table-driven code. The Object of Data Abstraction and Structure, David D. Riley © Addison Wesley pub.

3. Table-driven code is generally a good alternative to multi-way selection. Cost Per Burger QuantityItem Cost 0 $0.00 1 $1.50 2 $1.40 3 $1.35 4 or more $1.30 Table-Driven Version if (quantity < burgerCost.length) { System.out.println( quantity * burgerCost[quantity] ); } else { System.out.println( quantity * burgerCost[burgerCost.length-1] ); } What are the advantages to table-driven code? Selection Version if (quantity == 0) { System.out.println( 0 ); } else if (quantity == 1) { System.out.println( 1.5 ); } else if (quantity == 2) { System.out.println( 2 * 1.4 ); } else if (quantity == 3) { System.out.println( 3 * 1.35 ); } else if (quantity >= 4) { System.out.println( quantity * 1.3 ); } The Object of Data Abstraction and Structure, David D. Riley © Addison Wesley pub.

4. Sometimes the index numbering is different than the table. Days Per Month MonthLength 1) Jan 31 2) Feb 28 3) Mar 31... 12) Dec 31 Decoding Table Letter A B C D E F G H I J K L M N O P Q R S T U V W X Y Z Cypher X C B H T Z I D G Y Q P N M U L K W V E O S R A J F int[] monthLength = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}; Sometimes the the table is indexed with non-numerics. char[] cypher = {‘X’, ‘C’, ‘B’, ‘H’, ‘T’, ‘Z’, ‘I’, ‘D’, ‘G’, ‘Y’, ‘Q’, ‘P’, ‘N’, ‘M’, ‘U’, ‘L’, ‘K’, ‘W’, ‘V’, ‘E’, ‘O’, ‘S’, ‘R’, ‘A’, ‘J’, ‘F’ };

5. Using constants ( final variables) can be helpful for table-driven code. int[][] distance = { {0, 1025 2527 1441}, {1025, 0, 2214, 653}, {2527, 2214, 0, 2861}, {1441, 653, 2861, 0} }; int final albany = 0; int final atlanta = 1; int final boise = 2; int final miami = 3; Mileage Between Cities AlbanyAtlanta BoiseMiami Albany 0 1025 2527 1441 Atlanta 1025 0 2214 653 Boise 2527 2214 0 2861 Miami 1441 653 2861 0 The Object of Data Abstraction and Structure, David D. Riley © Addison Wesley pub.