This archive contains the example programs from "Ada 95: The Craft of Object-Oriented Programming" by John English (Prentice Hall 1997). This book is now out of print, so I've converted it to HTML format and released it online (see http://www.it.bton.ac.uk/staff/je/adacraft/). Errata from the printed copy of the book and minor errors from earlier versions of these examples have been corrected. The examples have been tested using GNAT 3.13p on Linux and Windows platforms.
The examples from each chapter are in separate subdirectories (ch02 through ch19, corresponding to chapters 2 through 19). Most chapters contain multiple examples, and these are in separate subdirectories called "egXX" where XX is the example number. There is also a "packages" subdirectory containing the final version of each of the major packages developed in the book. See the file "examples.txt" for a description of the examples supplied.
Since many of the files are used in more than one example, the distribution for Unix systems (adacraft.tar.gz) uses symbolic links to avoid unnecessary duplication of files. Take care if you want to modify any of the files, as you might end up modifying the master copy in the process! The distribution for Windows (adacraft.zip) doesn't use symbolic links, so many of the files are duplicated. The distribution is a bit bigger, but it also means that you don't need to worry about modifying a master copy of a file.
You can compile all the examples by running "sh build.sh" on Unix systems, or "build.bat" on Windows systems. This assumes that you have the GNAT compiler installed on your system.
The examples listed here are cross-referenced to the text. You can build all these examples using the build script supplied, or you can change to the appropriate directory and use the command "gnatmake TARGET -cargs -gnato" (e.g. change to ch02/eg01 and say "gnatmake hello -cargs -gnato").
- ch02/eg01/hello -- The very first "Hello world" program
- ch02/eg02/hello -- The same, but with no layout
- ch02/eg03/hello -- "Hello world" illustrating "use" clauses
- ch02/eg04/hello_3 -- Using Hello procedure from library in another program
- ch02/eg05/hello_3 -- The same, but done "by hand"
- ch02/eg06/sum -- Program to add two integers together
- ch02/eg07/hello -- "Hello world" illustrating use of "Put_Line"
- ch03/eg01/greetings -- Display "Good morning" or "Good afternoon"
- ch03/eg02/greetings -- The same, with nested "if" statement
- ch03/eg03/greetings -- The same but using "elsif"
- ch03/eg04/greetings -- The same, illustrating assignment statements
- ch03/eg05/greetings -- The same, illustrating compound conditions
- ch03/eg06/greetings -- The same, illustrating "case" statements
- ch03/eg07/greetings -- The same, illustrating "loop" and "exit"
- ch03/eg08/greetings -- The same, illustrating "exit when"
- ch03/eg09/calculator -- A simple calculator (two operands separated by operator)
- ch03/eg10/calculator -- The same, skipping spaces before operator
- ch03/eg11/calculator -- Left-to-right calculator (sequence of operands & operators)
- ch03/eg12/calculator -- The same, with exception handling
- ch03/eg13/get_integer -- Program to get an integer using exception handling in a loop
- ch04/eg01/weekday -- Find the day of the week using Zeller's Congruence
- ch04/eg02/weekday -- The same, with an internal procedure
- ch04/eg03/weekday -- The same, with an internal function
- ch04/eg04/weekday -- The same, with a separate function
- ch04/eg05/weekday -- The same, with a library function
- ch04/eg06/weekday -- The same, with a package
- ch04/eg07/weekday -- The same, with a hidden function in the package
- ch04/eg08/weekday -- The same, with package initialization
- ch04/eg09/weekday -- The same, with a child package
- ch04/eg10/weekday -- The same, with a child function
- ch05/eg01/greetings -- "Greetings" program using Ada.Calendar.Clock
- ch05/eg02/greetings -- The same, using constants
- ch05/eg03/greetings -- The same, using an enumeration type
- ch06/eg01/sort -- Shuffle sort an array of integers
- ch06/eg02/init_test -- Demonstration of record type auto-initialization
- ch06/eg03/weekday -- "Weekday" program using an enumeration for the month
- ch07/eg01/weekday -- Earlier version of "weekday" program with exception handling
- ch07/eg02/weekday -- The same, but using subtypes
- ch07/eg03/weekday -- The same, using Ada.Calendar to validate date
- ch07/eg04/weekday -- The same, illustrating "others" exception handler
- ch07/eg05/weekday -- The same, using a loop to get a valid date
- ch07/eg06/weekday -- The same, using a local variable
- ch07/eg07/weekday -- The same, but using Skip_Line to make it work properly!
- ch07/eg08/weekday -- The same, illustrating Exception_Name
- ch07/eg09/word_count -- Program to count words in a file
- ch08/eg01/diary -- Diary program, initial version with stubs
- ch08/eg02/diary -- The same, with debugging modifications
- ch08/eg03/diary -- The same, with first bug fix
- ch08/eg04/diary -- The same, with end-of-file bugfix
- ch08/eg05/diary -- The same, with List and Add implemented
- ch08/eg06/diary -- The same, with Delete implemented
- ch08/eg07/diary -- The same, with Load and Save implemented
- ch08/eg08/diary -- The same, final version of this approach
- ch09/eg01/date_test -- Test program for abstract data type for dates
- ch09/eg02/date_test -- The same, illustrating deferred constants
- ch09/eg03/date_test -- The same for improved date ADT
- ch09/eg04/date_test -- The same, illustrating bad use of operator overloading
- ch09/eg05/date_test -- The same, using wrapper for Ada.Calendar
- ch10/diary -- ADT-based appointments diary
- ch11/eg01/diary -- Appointments diary using linked list
- ch11/eg02/weekday -- "Weekday" program using ragged array for day names
- ch12/eg01/diary -- Appointments diary using generic linked lists
- ch12/eg02/sort -- Illustration of generic sorting procedure
- ch12/eg03/diary -- Illustration of generics and access-to-subprogram types
- ch13/eg01/calculator -- Stack-based calculator with precedence
- ch13/eg02/calculator -- The same, with parenthesised subexpressions
- ch13/eg03/calculator -- The same, with list-based stack package
- ch13/eg04/calculator -- The same, with opaque (array) type for stack
- ch13/eg05/calculator -- The same, with opaque (list) type for stack
- ch13/eg06/fact_test -- Illustration of recursive function to calculate factorials
- ch13/eg07/evaluate -- Calculator using a recursive descent parser
- ch14/eg01/diary -- Meetings diary, using embedded appointment in meeting type
- ch14/eg02/var_test -- Illustration of variant records
- ch14/eg03/diary -- Meetings diary using tagged type for appointments
- ch15/eg01/diary -- Heterogenous diary using dispatching
- ch15/eg02/diary -- The same, including a "deadline" type
- ch16/eg01/diary -- Diary, with explicit deallocation of deleted entries
- ch16/eg02/pointer_test -- Test program for "smart pointer" type
- ch17/calculator -- Calculator using object-oriented techniques
- ch18/spreadsheet -- Spreadsheet using extension of calculator from chapter 17
- ch19/eg01/task_test -- Illustration of multitasking
- ch19/eg02/task_test -- The same, with task discriminants
- ch19/eg03/task_test -- Illustration of task rendezvous
- ch19/eg04/test -- Illustration of unsafe access to global data
- ch19/eg05/test -- The same made safe using a protected record
- ch19/eg06/spreadsheet -- Extension of spreadsheet providing active cells
There are some known problems outstanding due to bugs in GNAT:
Affects: ch14/eg03, ch15/eg01, ch15/eg02, ch16/eg01
Status: GNAT 3.01 - 3.05
Symptom: The common appointment part of derived appointments gets
lost (and dates usually appear as 1-JAN-1970 as a result).
Interestingly enough, extension aggregates used to work
properly in GNAT 2.07... :-(
Solution: Upgrade to GNAT 3.07 or later where the problem has been fixed,
or copy the files in the ch14/ch15/ch16 subdirectories of the
"fixes" directory to the corresponding chapter subdirectories.
These do everything the long way round, avoiding the use of
extension aggregates.
Affects: ch15/eg01, ch15/eg02, ch16/eg01
Status: GNAT 3.01
Symptom: GNAT 3.01 incorrectly reports an error when 'Class'Input or 'Class'Output are used with for an abstract class. To get around this, the abstract parent type can be derived from a concrete type which can then be used to call 'Class'Input or 'Class'Output. Unfortunately this won't help; loading a diary will fail, usually with a Data_Error. This is because the 'Class'Input routine skips some of the data as it reads the file (but 'Class'Output works fine!).
Solution: Upgrade to GNAT 3.03 or later, where the problem has been fixed.
Affects: ch18
Status: GNAT 3.01 (only under SunOS)
Symptom: Cells containing formulas which reference empty cells will crash with a protection fault. An Undefined_Cell_Error is being raised but never gets to its handler.
Solution: Upgrade to GNAT 3.03 or later where the problem has been fixed, or use GNAT 3.01 under any other operating system.
Affects: ch19 (all)
Status: GNAT 3.01 - 3.03 (MS-DOS)
Symptom: All examples from chapter 19 fail to link with the MS-DOS port of the compiler.
Solution: Use a different operating system, or upgrade to GNAT 3.04 or later.
Affects: ch19/eg02, ch19/eg06
Status: GNAT 3.01
Symptom: Discriminant values are not passed correctly to tasks, so the task test program in example 2 will be executed a random (usually large!) number of times.
Solution: Upgrade to GNAT 3.03 or later, where the problem has been fixed.
Affects: ch19/eg06
Status: GNAT 3.01 - 3.08
Symptom: If a task is used as a component when deriving from a tagged type, the compiler will crash with an assertion error if you try to create an object of the derived type using "new".
Solution: Copy the files in the ch19 subdirectory of the "fixes" directory to the corresponding chapter subdirectory. This uses a pointer to a task as the record component rather than using a task; the constructor function is modified to create the task using "new" and assign the resulting pointer to the record component. Note that under GNAT 3.01 the program will then compile but it will crash when you try to run it because the task discriminant (a pointer to the spreadsheet) will have been passed to the task incorrectly, as described above.
Affects: ch19/eg06
Status: GNAT 3.01 - 3.08 (SunOS, Solaris, Win95/NT)
Symptom: Get_Immediate ignores keyboard input (except ^C) under SunOS and Solaris; under Windows 95/NT it behaves like Get (i.e. it blocks until the Enter key has been pressed). It works fine under other operating systems.
Solution: Use a different operating system, or upgrade to GNAT 3.05 or later in the case of SunOS/Solaris.
The compiler bugs have been reported to the GNAT development team, so hopefully they will be fixed in a future release. Any other bugs are entirely my fault; please email me at the address below if you discover any, or if you have any other comments or suggestions to make. Note that I have deliberately left some examples incomplete (e.g. the lack of Data_Error handling in the diary package's Load procedure) so that readers still have some work to do; these omissions are features, not bugs (:-). The documentation in the examples is also minimal; it's all in the book (implication: buy the book!). And most importantly of all, have fun learning Ada 95!
-- John English ([email protected]).