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CS 15 Project 2: CalcYouLater
February 22, 2022
Contents
Introduction 3
Preamble . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Note on File I/O . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Project Planning and Deliverables 5
Week One . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Deliverable #1: Design Checkoff . . . . . . . . . . . . . . . . 5
Deliverables #2 and #3: DatumStack and parseRString . . . 6
Week Two . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Deliverable #4: CalcYouLater . . . . . . . . . . . . . . . . . . 6
Datum Class 7
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Datum Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
File Organization for the Provided Datum Files . . . . . . . . . . . 8
DatumStack Class 10
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
DatumStack Interface . . . . . . . . . . . . . . . . . . . . . . . . . 10
RPNCalc Class 12
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
RPNCalc Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
The‘Simpler’RPNCalc Commands . . . . . . . . . . . . . . . . . 12
The‘more Complex’Commands . . . . . . . . . . . . . . . . . . . 13
Any rstring . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
exec . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
file . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
if . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
1
CONTENTS 2
Handling Errors in RPNCalc::run . . . . . . . . . . . . . . . . . . . 17
Unrecognized Input . . . . . . . . . . . . . . . . . . . . . . . . 17
Exception Handling . . . . . . . . . . . . . . . . . . . . . . . 17
Errors while getting command parameters from the stack . . 18
Error output prints to std::cerr . . . . . . . . . . . . . . . . . 19
parseRString Specification 20
parseRString Implementation . . . . . . . . . . . . . . . . . . . . . 20
Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
cylc and cyl files 22
Implementation Notes and Advice 23
Notes Regarding the Starter Code . . . . . . . . . . . . . . . . . . 23
Files to Submit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
DatumStack Implementation . . . . . . . . . . . . . . . . . . . . . 25
Other Tips . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Getting started . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Makefile . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
README . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Submitting Your Work . . . . . . . . . . . . . . . . . . . . . . . . . 27
Introduction
Preamble
Welcome to the second project! It’s a calculator, but it’s even more. It’s
almost a real programming language! This is a more involved project, for
which you have been given ample time, if you start right away.
Do not try to do it in one sitting
Read it right away. Jot down and draw ideas. It’s better to work on it in
90 minute or 2 hour chunks of time. If you do that, and you’re organized,
it will go smoothly. The stack implementation itself should be doable in a
single sitting. Be sure to note the three phases of the project. Come in to
talk to one of us about your plan as early as you can.
Note on File I/O
For this project, you’ll find knowledge you acquired about file I/O in Project
1 helpful. In particular, the ability to pass a reference to an std::istream
to a function makes it easy to modularize your code by allowing a function
to process input from any input stream, whether it be std::cin or a stream
that you attached to a file using open.
There is an additional piece here. C++ has a way for you to treat a
std::string as if it were an input stream! It has a class,
called std::istringstream. Its constructor and an example of how to use
a std::istringstream for input can be found here. A istringstream
has eof and fail member functions, just like std::cin or any other input
stream. Here is also a tutorial on string streams. The idea for
our purposes is to make an std::istringstream from a std::string,
and then pass that std::istringstream to a function that requests an
std::istream &, and it will work!
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CONTENTS 4
Introduction
In this project you will implement a Reverse Polish Notation (RPN) calculator.
RPN is also known as“postfix”notation1
. This means that the
operator comes after its operands rather than in between. For example:
• 3 4 + is equal to 7
• 3 4 * is equal to 12
• 1 2 – is equal to -1 (note the order)
• 8 2 / is equal to 4 (note the order)
Cool fact: RPN does not need any parentheses as long as each operator
has a fixed number of operands (which is the case in this assignment). For
example, the infix expression:
5 + ((1 + 2) * 4) – 3
can be written in postfix notation as follows:
5 1 2 + 4 * + 3 –
Your RPNCalc will support more than just integers, however! It will support
Datum objects! More on this in a moment.
1The notation you’re used to, with the operator between the operands is called“infix”
notation.
Project Planning and
Deliverables
Before writing any functions, sit down and read the assignment specification
in full. There is a lot of complexity here! Then, begin to plan your solution.
It would be prudent to organize and plan your solution to be as modular as
possible. Use helper functions! Doing this initial planning will be extremely
helpful down the road when it comes to testing and debugging; it also helps
the course staff more easily understand and read your work (which can only
help you). It is not advisable that you sit down and attempt to write this
in one sitting, particularly if that sitting is close to the deadline. For that
reason, the CS 15 course staff has come up with a project implementation
plan, split into three required (read: graded) phases:
Week One
Deliverable #1: Design Checkoff
Go into office hours and talk to a TA about your plan. Bring some drawings
of your data representations – how you imagine your data will flow between
structures. This helps twofold: you plan out your project and get your brain
working on it in the background, and also you get design feedback before
it’s too late. You must have physical drawings to show the TA. The TA will
not look at any code since this checkout is designed to give feedback on your
design only, not any code (light pseudocode is allowed). TAs will check off
your design and reserve the right to not check off your design if you do not
have drawings (and pseudocode) to show or if a TA feels like your design
was not thoroughly mapped out enough. Please sign up for design check off
linked here
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CONTENTS 6
Deliverables #2 and #3: DatumStack class and parseRString
Write and submit the DatumStack class and parseRString function (these
are described in detail under sections of their own names below). These are
not expected to be strenuous exercises, but have been known to occasionally
hide latent bugs that mess up the rest of your RPNCalc. So, start them early,
get them right, and make sure they are well-tested.
Week Two
Deliverable #4: CalcYouLater
Write CalcYouLater! (described in detail below) Implement some of the
less involved operations first. Then do the more complicated operations.
Datum Class
Introduction
Before diving in to the details of the RPNCalc and DatumStack clases, we
will go over the Datum class. A Datum object is essentially a container for
one of three things:
• int
• bool
• rstring (short for RPN string)
The type of the value contained by any given Datum object is chosen from
the above three options at construction-time, and does not change during
the lifetime of that Datum object. We have coded the Datum class for you,
but it would be worth your while to understand the interface.
Datum Interface
• Four Constructors: one constructor for each type a Datum object can
contain, plus a copy constructor. Note that there is no default constructor.
Also note that, under the hood, rstrings are represented as
C++ strings.
1 Datum (int i) ;
2 Datum (bool b) ;
3 Datum (string s) ;
4 Datum (const Datum &d) ;
• A destructor
• An assignment operator overload
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CONTENTS 8
• Three type query functions:
1 bool isInt () ;
2 bool isBool () ;
3 bool isRString () ;
• An equals (==) operator for comparing two different Datum objects.
This allows us to call, e.g., d1 == d2 where d1 and d2 are instances
of the Datum class. If d1 and d2 contain values of different types, this
would return false. If d1 and d2 contain values of the same type,
then the underlying values will be compared.
• The less-than (<) operator for Datum holding integers. Using the lessthan
operator and the is-equal-to operator, we can build less-than-orequal
(<=), greater-than-or-equal (>=), and greater-than (>). Use of
any of these operators on Datum which hold booleans or rstrings will
raise a std::runtime_error with the message“datum_not_int”.
• Three data access functions:
1 int getInt () ; // throws ” datum_not_int “
2 bool getBool () ; // throws ” datum_not_bool “
3 std :: string getRString () ; // throws ” datum_not_rstring “
These functions each throw an std::runtime_error with the associated
message above if they are called on a Datum of the wrong type.
For instance, if I have a Datum that contains a boolean value, and I
call getRString() on it, it will raise a std::runtime_error with the
message datum_not_rstring.
• toString(), a function that creates a string representation of the
Datum. This is useful for printing and debugging.
File Organization for the Provided Datum Files
The Datum class is given to you as two files: Datum.h and Datum.o. Datum.h
contains the interface of the Datum class; Datum.o contains a pre-compiled
object file. That is, it is a non-human-readable file which was compiled from
a .cpp file, and it contains all of the working machine code that you can use
in your project, but does not give you any information about how it works.
What it does, however, can be gleaned from Datum.h (the interface). To use
the Datum class, you must #include “Datum.h” at the top of whichever file
CONTENTS 9
will use it, and you must link Datum.o with your compiled code. You can
review the Makefile lecture and lab for a reminder of how to link with a .o
file.
DatumStack Class
Introduction
The DatumStack class will maintain a stack of Datum objects, and will be
used heavily by the RPNCalc class. Part of your Week 1 assignment is to to
implement this interface.
DatumStack Interface
You DatumStack class must have the following interface (all the following
members are public):
• Two constructors as follows:
◦ A default constructor, which takes no parameters and initializes
an empty stack.
◦ A constructor which takes an array of Datum and an integer
specifying the size of the array as parameters and creates a stack
initialized so that the elements of the array are on the stack with
the array’s element 0 pushed on first and it’s (size – 1)th element
at the top of the stack. Example:
1 Datum data [2] = {Datum (5) , Datum (true) };
2 DatumStack d(data , 2) ;
3 // d now has a true Datum as the top element
• If necessary, define the Big Three (destructor, copy constructor, assignment
operator).
• An isEmpty function that takes no parameters and returns a boolean
value that is true if this specific instance of the DatumStack class is
empty and false otherwise.
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CONTENTS 11
• A clear function that takes no parameters and has a void return type.
It makes the current stack into an empty stack.
• A size function that takes no parameters and returns an integer value
that is the number of Datum elements on the stack.
• A top function that takes no parameters and returns the top Datum
element on the stack. NOTE: It does not remove the top element
from the stack. If the stack is empty, it throws a std::runtime_error
exception with the message“empty_stack”.
• A pop function that takes no parameters and has a void return type.
It removes the top element on the stack. NOTE: It does not return
the element. If the stack is empty it throws a std::runtime_error
exception with the message“empty_stack”.
• A push function that takes a Datum element and puts it on the top of
the stack.
RPNCalc Class
Introduction
The interface for the RPNCalc class is rather straightforward—the complexity
is not in the number of functions, but rather is in the logic of processing
the commands that come to the run function.
RPNCalc Interface
• Define a default constructor which takes no parameters and initializes
the RPNCalc object.
• Define a destructor that destroys/deletes/recycles any heap-allocated
data you may have used in the RPNCalc instance.
• Define a run function that takes no parameters and returns nothing.
This function reads in commands from standard input (std::cin).
Each command can be read as a string and commands will be separated
by whitespace. Commands do not have to be on different lines. See
below for details.
The‘Simpler’RPNCalc Commands
The supported operations will be extended by the“harder”commands, but
implement these simpler commands first and get them working before continuing
on.
• A number causes a Datum containing the number to be pushed onto
the stack.
• #t causes a Datum with the boolean true to be pushed on the stack.
12
CONTENTS 13
• #f causes a Datum with the boolean false to be pushed on the stack.
• not reads and pops the top element off the stack, a boolean, and causes
a Datum with the opposite boolean value of the popped element to be
pushed on the stack.
• print prints the value on the top of the stack to std::cout (without
popping it) followed by a new line.
• clear clears the calculator, emptying the stack.
• drop causes the top element on the stack to be removed.
• dup duplicates the top element on the stack.
• swap swaps the top two elements on the stack.
• quit, quits the calculator completely. When the program quits, it
prints the following message to std::cerr:“Thank you for using
CalcYouLater.\n”(It should print this message whether it quits with
the quit command or by reaching the end of input on std::cin).
• The operators +, -, *, /, or mod. Any of these causes the top two
elements (which must both be integers) to be popped off the stack,
the operation to be performed on them (addition, subtraction, multiplication,
division, or remainder), and a Datum with the result to be
pushed on the top of the stack. The first operand of the operation is
the first (deeper) item on the stack. NOTE: The result does not
print.
• The operators <, >, <=, >=, or ==. Any of these causes the top two
elements to be popped off the stack, the operation to be performed on
them (some kind of logical comparison) and a Datum with the result
(a boolean) to be pushed on the top of the stack. The first operand
of the operation is the first (deeper) item on the stack. NOTE: The
result does not print.
The‘more Complex’Commands
Any rstring
You can think of an rstring as a sequence of commands to be saved and
executed later. For our purposes, an rstring will be defined as a sequence
of characters that follows this pattern:
CONTENTS 14
• The sequence must begin with “{” (note the spacing!).
• The sequence must end with ” }” (note the spacing!).
Any rstring that is provided as input to RPNCalc will be put inside of a
Datum as an std::string, and the Datum will be pushed onto the stack. To
clarify,“rstring”itself is not a command; rather, an example of a command
that would be parsed as an rstring and pushed onto the stack would be
“{2 8 +}”. Another example would be“{2 +}”.
Note: The braces must match up, and the spacing around the
beginning and ending braces must be correct. Also, rstrings can
be nested – to see an example of nested rstrings, read on about
if.
Clearly, processing rstrings will be important for the success of your
RPNCalc class. Thus, part of your Week 1 assignment is to implement a
function to parse rstrings. While reading in input, once you read a “{“,
you should call this parsing function. See the section titled parseRString
Specification (below) for details.
exec
exec takes the topmost element on the stack, which must be an rstring, and
processes its contents as a sequence of commands. If the topmost element
of the stack is not an rstring, it should print“Error: cannot execute non
rstring\n”to std::cerr, and your program should continue to accept input.
file
file pops the top element off of the stack, which must be an rstring. If
it is not an rstring it should print“Error: file operand not rstring\n”to
std::cerr, and continue to accept input.
For example, the rstring might be“{square.cylc}”, in which case
the filename is“square.cylc”. The contents of the named file is then read and
processed as if its commands had been typed into the command loop. If the
file cannot be opened or read, the message“Unable to read FILENAME\n”
(where“FILENAME”is replaced with the name of the file specified in the
command) is printed to std::cerr. The program does not crash or throw
an exception. The command loop then continues reading data from its last
input source.
CONTENTS 15
if
if Overview
if has a few steps. The command if:
- pops an rstring off of the stack—this rstring will be executed if the
condition is false. - pops another rstring off of the stack—this rstring will be executed
if the condition is true. pops a boolean off of the stack—this is the condition to test.
To clarify, if assumes that the stack will look like this at the time it is
called:
top : | FalseCase |
| TrueCase |bottom : | TestCondition |
If the test condition is the boolean true, then the TrueCase in the diagram
above should be exec’d. If the test is the boolean false, the FalseCase
in the diagram above should be exec’d. If any of the elements encountered
are of the wrong type, choose the appropriate error message to print to
std::cerr:
•“Error: expected rstring in if branch\n”
•“Error: expected boolean in if test\n”
Your program should not throw an exception. After printing to std::cerr,
it should continue accepting input.
if Examples
Here are some examples of if in action that you might find helpful. Please
note that the > characters below are the prompt (which you should not
output, but we have included for readability in this document), not the
greater-than sign.
CONTENTS 16
useless if input to RPNCalc3 4 <
{#t} {#f} if
printt
translated to C++
- if (3 < 4) {
- return true ;
- } else {
- return false ;
}
if that mimics the behavior of“not”3 4 <
{#f} {#t} if
printf
translated to C++
- if (3 < 4) {
- return false ;
- } else {
- return true ;
}
A more complicated nested if4 dup 10 ==
{1 0 /}
{6 + dup 10 < { 10 >} {10 ==} if }
if
printt
Which should read as follows:
• Push 4 onto the stack twice. Check if 4 is equal to 10.
• If so, execute the rstring“{1 0 /}”.
• If not:
CONTENTS 17
◦ try adding 6 to the 4 on the stack.
◦ check if that result is smaller than 10 (it shouldn’t be).- If it is, check if it is greater than 10 (it shouldn’t be).
- If it is not, check if it is equal to 10 (it should be).
translated to C++ - if (4 == 10) {
- return 1 / 0;
- } else {
- if (4 + 6 < 10) {
- return 10 > 10;
- } else {
- return 10 == 10;
- }
}
Just For Fun Exercises!
• set followed by the name of a variable causes the variable to be set to
the value on the top of the stack, which is then popped.
• get followed by the name of a variable pushes the value of the variable
onto the stack. If the variable has not yet been defined, print the
variable name and then“: undefined”on std::cerr (e.g.“x: unde-
fined”). It should not throw an exception. After printing, it should
continue accepting input.
Handling Errors in RPNCalc::run
Unrecognized Input
For any other input that is not a recognized command, print the offending
input and print“: unimplemented”to std::cerr followed by a newline (e.g.
“x: unimplemented\n”). It should not throw an exception. After printing,
it should continue accepting input.
Exception Handling
Your RPNCalc class should catch any exceptions that may be thrown from
the DatumStack class. If the DatumStack class throws an exception the
CONTENTS 18
RPNCalc should print the string associated with the exception to std::cerr.
For example if the stack threw an std::runtime_error exception with the
message“empty_stack”, the RPNCalc should print“Error: empty_stack\n”
to std::cerr, then continue to accept input.
Note: the exception message from the DatumStack class does not include
“Error:”, but RPNCalc should print the error message given when the
exeception is (or would be) thrown.
Your run() function should also catch all other exceptions thrown during
evaluation. For example, since the Datum class can throw std::runtime_errors,
you should catch those and print them appropriately to std::cerr:
•“Error: datum_not_int\n”
•“Error: datum_not_bool\n”
•“Error: datum_not_rstring\n”
You can review the lecture on Exceptions for a reminder of how to catch
exceptions and print the corresponding exception message.
We expect your program to never crash. This means you must test for
possible edge cases. If you come up with an edge case, you MUST use
the reference implementation to determine what the behavior of your
program should be for that case, as we will be using the reference,
and the exact error messages for grading your assignment.
Errors while getting command parameters from the stack
When running a command that must pop off parameters from the stack,
RPNCalc’s run should first pop both elements off of the stack, and then
display the first error enountered, then continue processing input from the
input source. That means that all parameters that had been popped off by
the error producing command will be discarded.
Example: Datum of wrong type when running the + command
The + command expects that the first two elements on the stack are ints.
If the + command was run on a stack that had a Datum that wasn’t an int
at the top, e.g.:
top : | rstring |
| int |bottom : | boolean |
CONTENTS 19
Then the approriate error message should be output and the run function
should continue processing input. All Datum that had popped off by + leading
up to the error would have been discarded, i.e the stack would look like:
top : | boolean |bottom : | |
Error output prints to std::cerr
As mentioned above, all error output (and the final program termination
message) is sent to std::cerr. The only program output that goes to
std::cout is generated when print command is sent to RPNCalc.
parseRString Specification
Introduction and Function Signature
Implementing the parseRString function will be required as part of your deliverables
for Week 1. Specifically, you will submit a file called parser.cpp.
It should contain one function called parseRString which takes a reference
to an istream, as a parameter to continue reading input from. The function
signature will be as follows- std :: string parseRString (std :: istream & input) ;
parseRString Implementation
Assume this function is called after an initial“{”has been read from the
input stream passed as a parameter. parseRString continues reading input
from the stream until all curly braces are matched or until it reaches the
end of the input. It returns an rstring (i.e, an std::string), with the
preceding rstring specifications.
Examples
Example 1: {1 2 +}
Call parseRString after you see the first {
That is , pass ” 1 2 + }” or ” 1 2 + }” to parseRString
It should return the string “{1 2 +}”
Example 2: {1 { 4 2 /} / }”
Call parseRString after you see the first {
That is , pass ” 1 {4 2 /} / }” or ” 1 {4 2 /} / }”
It should return the string : “{1 { 4 2 /} / }”
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CONTENTS 21
Note: parseRString assumes, therefore, that the first“{”has already been
processed, and returns a complete rstring based on the information after
that. If you just call parseRString immediately before the first“{”, it will
print two“{”characters. This is expected behavior. Later, you will find this
function useful when reading in an rstring as input—it allows you to read
in a complete rstring, with balanced braces, thereby enabling RPNCalc to
handle nested rstrings.
If parseRString gets to the end of the input stream without finding the
final matching “}”,then you can choose what to do. Throwing an exception
would be reasonable. We will not test you on this case.
cylc and cyl files
RPNCalc runs on files with extension .cylc. For example, if you have a
sequence of commands saved in my_example.cylc, you can execute them
by either:
• Sending the file to cin on the command line by using <, i.e., running
./CalcYouLater < my_example.cylc
• Pushing the rstring“{my_example.cylc}”on to the stack, then
using the file command.
Often, .cylc files can be tricky to read and understand. Thus, you can also
use .cyl files, which allow you to add comments. In .cyl files, comments
begin with the character %. Because RPNCalc does not support comments,
you must then convert the .cyl file to a .cylc file. We have given you a
program called cylc that does this for you.
As examples, we have provided you with four .cyl files in the starter
code: add.cyl carries out some simple additions, fact.cyl implements
the factorial function using RPNCalc commands, fib.cyl implements the
Fibonacci function, and fib_debug.cyl uses Fibonacci to demonstrate a
way to debug RPNCalc programs. Take a look at these files and the comments
within them! They will be a useful reference when it comes time to test your
program.
In order to convert the above files to .cylc files that can actually be
run, use the cylc program we have provided you. For example, you can
run ./cylc fact.cyl. This will create a new file called fact.cylc, which
contains no comments or blank lines, and which can therefore be run by
CalcYouLater.
22
Implementation Notes and
Advice
You will write both the DatumStack and RPNCalc classes from scratch. They
will each have two files associated with them – a .h file and a .cpp file. In
addition to the public interfaces for the class defined above, you are free to
add any private member functions / variables that you wish.
• The names of your functions / methods as well as the order
and types of parameters and return types of the interface of
the DatumStack and RPNCalc classes and the parseRString
functions defined above must be exactly as specified. This is
important because we will be compiling and linking the code
you wrote with our own client code!
• Any print statements or exception messages should likewise
print exactly as specified and use the given error type.
• For the two classes, you may not have any other public functions.
• All data members must be private.
• You may not use std::stack or any other built-in facility that
would render the assignment trivial.
Notes Regarding the Starter Code
To get the starter materials, run the following command, which will give you
copies of a few files plus links to Datum.h, Datum.o, and theCalcYouLater
reference implementation.
23
CONTENTS 24
/ comp /15/ files / proj2 / setup
Note – do not manually copy the files, just run the command.
• The file Datum+vector_example.cpp in the starter code demonstrates
the basic usage of the Datum class.
• The file, got_int.cpp, contains a function got_int that can test
whether a string can be interpreted as an integer, and, if so, what
the value of the integer is. You may use this function as-is: just put it
into your file. You should understand how the parameter works, but
you do not need to know the details of the implementation.
• The binary file theCalcYouLater is a reference implementation that
you may refer to to help you understand what you are supposed to do,
and to help you test your own implementation.
• The other files are described further in other sections
Files to Submit
The following files for this assignment will be written from scratch:
DatumStack . h
DatumStack . cpp
RPNCalc . h
RPNCalc . cpp
main . cpp
README
Makefile
You must also submit:
• Any unit tests you write for your program. This may be done in a file
called unit_tests.h, using the unit_test framework that we have
used on past assignments. Alternatively, you can create your own testing
main functions, e.g., submit a file called DatumStack_tests.cpp
with a main function that calls out to tests. Whatever testing files you
use, you must submit them!
• Any command files (.cyl files that you used for testing, i.e., files that
you ran with RPNCalc using the file command). You should have
some command files!
CONTENTS 25
The files DatumStack.h and RPNCalc.h will contain your class definitions
only. The files DatumStack.cpp and RPNCalc.cpp will contain your implementations.
main.cpp will contain your main calculator program. The
Makefile will contain the instructions for make to compile your program.
README will have the sections described in README Outline section below.
DatumStack Implementation
Implement DatumStack however you like. We suggest using a LinkedList or
an ArrayList as discussed in class. You may use std::vector or std::list
but you must NOT use std::stack.
Other Tips
DO NOT IMPLEMENT EVERTHING AT ONCE!
DO NOT WRITE CODE IMMEDIATELY!
Before doing anything, use the the reference program to get a sense of how
things work. This may seem like a lot, but if you break it into pieces,
it’s perfectly manageable. Before writing code for any function, draw before
and after pictures and write, in English, an algorithm for the function. Only
after you’ve tried this on several examples should you think about coding.
Getting Started
To get up and running, - create the two files for the classes DatumStack and RPNCalc
- start filling in the .h file
include the .h file in the .cpp file
- define an empty main function in a main.cpp file (just return 0)
- compile!
If you start with the DatumStack class (follow a similar pattern if you start
with the RPNCalc class): - Implement just the default constructor first. Add a single variable of
type DatumStack to your test main function; compile, link, and run.
CONTENTS 26 - Now you have some choices. You could add the destructor next, but
certainly you should add a print function for debugging soon. Make it
private before submitting.
You will add one function, then write code in your test file that performs
one or more tests for that function. Write a function, test a function, write
a function, test function. . . Follow the same testing approach for every class
you write, and add functionality little by little.
For the RPNCalc class, the first version of the run() function should
accept only the quit command. Then it should read any number of items,
just printing them, until there’s a quit or until reaching end of file. Then
start to add items bit by bit. Add numbers, and print the stack to make
sure they get on the stack correctly. Then add the operators one at a time,
comparing your results with the reference. Do the file command last.
You may want to refactor your program when you get to the file command;
don’t duplicate the command logic in two places. If you pass file
streams around, you should do so using C++ reference parameters. The
example program we provide shows how.
If you need help, TAs will ask about your testing plan and ask to see
what tests you have written. They will likely ask you to comment out the
most recent (failing) tests and ask you to demonstrate your previous tests.
Makefile
We have given you a Makefile that knows how to make .cylc files from .cyl
files, but you must fill in the rest. Your CalcYouLater program must build
when we run make CalcYouLater, and must produce an executable named
“CalcYouLater”which can be run by typing ./CalcYouLater.
README
With your code files you will also submit a README file. You can format your
README however you like. However it should have the following sections:
A The title of the homework and the author’s name (you)
B The purpose of the program
C Acknowledgements for any help you received
CONTENTS 27
D The files that you provided and a short description of what each file
is and its purpose
E How to compile and run your program
F An outline of the data structures and algorithms that you used. Given
that this is a data structures class, you need to always discuss the the
data structure that you used and justify why you used it. Please
discuss the features of the stack data structure and also include (with
some justification/explanation) two other situations/circumstances/problems
where you could utilize a stack. The algorithm overview is always
relevant. Please pick a couple interesting/complex algorithms to discuss
in the README.
G Details and an explanation of how you tested the various parts of
assignment and the program as a whole. You may reference the testing
files that you submitted to aid in your explanation.
Each of the sections should be clearly delineated and begin with a section
heading describing the content of the section. You should not only have the
section letter used in the outline above.
Submitting Your Work
Be sure your files have header comments, and that those header comments
include your name, the assignment, the date, and acknowledgements for any
help you received (if not already credited in the README file).
For phase 0, there is nothing to provide, but you must have your design
reviewed by a member of the course staff. Come in to office hours and see
someone. Bring your design, which should include pictures of your data
structures, lists of functions you will need, etc.
For phase 1, the command is:
provide comp15 proj2_calcyoulater_phase1 DatumStack . h \
DatumStack . cpp parser . cpp README \
unit_tests . h …
Don’t forget to include your rstring parser code. The README doesn’t
have to be the final README. Just document anything that you feel we should
know about your DatumStack, parser, or the project in general.
For the final submission, the command is:
CONTENTS 28
provide comp15 proj2_calcyoulater DatumStack . h DatumStack . cpp \
unit_tests . h RPNCalc . h \
RPNCalc . cpp main . cpp README Makefile …
where“. . .”means any other files necessary to build your program as
well as any test code (e. g., .cyl files) you would like us to see. For example,
if you have another class, you should name the .h and .cpp files for that
class there.
Finally, as with previous assignments, after you have submitted for the
final time, you must fill out the Project 2 Final Survey on Gradescope.
CalcYouLater!
