CS253 HW7: Iteration!                

Changes                

It is not defined whether or not calling .set_wanted() has any effect on game play. That is, a call to .set_wanted() might restrict the words available for .select_target(), or it might not.                 

Description                

You will add iteration to your work in HW5. Iterating over a Game via Game::iterator or a for-each loop, will produce a list of words read from the supplied dictionaries, filtered by .set_length(), and additionally filtered by a user-supplied function. This is a forward iterator.                 

Methods                

The following methods & operators must work, where git is a Game::iterator object:                 

Game::set_wanted(wanted)

The argument, called the wanted-function, is a function (not a method) that takes a std::string by value, and returns true iff the word is to appear in for-each loop output. If this method is not called on a given Game object, then it is if the default wanted-function always returns true. Each call to .set_wanted() replaces any previous calls—the effects are not cumulative.

Write a wanted-function like this:

        // Accept only words that start with “th”:
        bool th(string s) {
            return s[0]=='t' && s[1]=='h';
        }

        Game g;
        g.set_wanted(th);
        g.add_dict("data177777.txt");
        for (string s : g)
            cout << s << '\n';  // only words starting with “th”.

Game::begin()

Return an object of type Game::iterator that “points” to the first word in the dictionaries of the proper length (per .set_length() or its default value) for which the wanted-function returns true.

Game::end()

Like .begin(), but “points” past the last such qualifying word.

++git

Increment the iterator, returning the new value.

git++

Increment the iterator, returning the old value, before it was incremented.

*git

Yields a string that corresponds to the iterator’s position in the words.

git == git

git != git

Compares two iterators for equality or inequality. Any other comparisons are undefined operations.

copy, assignment

Iterators are copy-constructable, and assignable.

The types and names in the method descriptions, above, do not determine the C++ declarations of those methods. They only serve to informally describe what sort of arguments a method might take. You might pass certain arguments by reference, use const, declare return types, etc.                 

Const-correctness, for arguments, methods, and operators, is your job. For example, it must be possible to call .begin() on a const Game, use * on a const iterator, or to copy a const iterator to a non-const iterator.                 

You may define other methods or data, public or private, as you see fit. You may define other classes, as you see fit. However, to use the Game or Game::iterator classes, the user need only #include "Game.h", not any other header files.                 

Hints                

• A nested (inner) class is not a derived class, and so has no access to the data or methods of the outer class. That is, a given Game::iterator object doesn’t intrinsically know which Game object it’s associated with.
• Your Game::iterator object really should contain a pointer to the associated Game object, so it has access to everything in the Game object. That way, you won’t be tempted to copy things from the Game object into the iterator object.

    export STACK_FRAME_LINK_OVERRIDE=ffff-ad921d60486366258809553a3db49a4a

Libraries                

libhw7.a is a library file. It contains a number of *.o (object) files. It must contain Game.o, but it may also contain whatever other *.o files you need. The CMakeLists.txt shown creates libhw7.a. It does not contain main().                 

To be explicit, the provided CMakeLists.txt does:

• creates Game.o by compiling Game.cc
• creates a library libhw7.a from Game.o
• creates test.o by compiling test.cc
• creates an executable called test by linking test.o with libhw7.a.

The tar file must contain at least all the files required to do this.                 

Testing                

You will have to write a main() function to test your code. Put it in a separate file, and do not make it part of libhw7.a. Particularly, do not put main() in Game.h or Game.cc. You will also have to create Game.h, and put it into hw7.tar. We will test your program by doing something like this:                 

    mkdir a-new-directory
    cd the-new-directory
    tar -x </some/where/else/hw7.tar
    cmake . && make
    cp /some/other/place/test-program.cc .
    g++ -Wall -std=c++17 test-program.cc libhw7.a
    ./a.out

We will supply a main program to do the testing that we want. You should do something similar. It’s your choice whether to include your test program in your hw7.tar file. However, cmake . && make must work. If it fails because you didn’t package test.cc, but your CMakeLists.txt requires test.cc, then your build failed, and you get no points. Test your tar file, not just your code.                 

Sample Run                

Here is a sample run, where % is my shell prompt:                 

% cat CMakeLists.txt
cmake_minimum_required(VERSION 3.11)
project(hw7)

# Are we in the wrong directory?
if (CMAKE_SOURCE_DIR MATCHES "[Hh][Ww]([0-9])$")
    if (NOT PROJECT_NAME MATCHES "${CMAKE_MATCH_1}$")
        message(FATAL_ERROR "Building ${PROJECT_NAME} in ${CMAKE_SOURCE_DIR}")
    endif()
endif()

# Using -Wall is required:
add_compile_options(-Wall)

# These compile flags are highly recommended, but not required:
add_compile_options(-Wextra -Wpedantic)

# Optional super-strict mode:
add_compile_options(-fmessage-length=80 -fno-diagnostics-show-option
    -fstack-protector-all -g -O3 -std=c++17 -Walloc-zero -Walloca
    -Wconversion -Wctor-dtor-privacy -Wduplicated-cond
    -Wduplicated-branches -Werror -Wextra-semi -Wfatal-errors
    -Winit-self -Wlogical-op -Wold-style-cast -Wshadow
    -Wunused-const-variable=1 -Wzero-as-null-pointer-constant)

# add_compile_options must be BEFORE add_executable.

# Create the executable from the source file main.cc:
add_library(${PROJECT_NAME} Game.cc)
add_executable(test test.cc)
target_link_libraries(test ${PROJECT_NAME})

# Create a tar file every time:
add_custom_target(${PROJECT_NAME}.tar ALL COMMAND
    tar -cf ${PROJECT_NAME}.tar *.cc *.h CMakeLists.txt)

% cmake . && make
… cmake output appears here …
… make output appears here …
% cat greek.txt
alpha
beta
gamma
delta
epsilon
zeta
eta
theta
iota
kappa
lambda
mu
nu
xi
omicron
pi
rho
sigma
tau
upsilon
phi
chi
psi
omega
% cat test.cc
#include "Game.h"
#include <cassert>
#include <iostream>

using namespace std;

// Reject words containing the letter ‘e’:
bool no_e(string s) {
    return s.find('e') == s.npos;
}

int main() {
    Game g;
    g.add_dict("greek.txt");

    for (auto s : g)
        cout << "all: " << s << "\n";

    g.set_wanted(no_e);
    for (auto s : g)
        cout << "no e: " << s << "\n";

    g.set_wanted([](string s) { return s[0] == 'z';});
    for (auto s : g)
        cout << "z: " << s << "\n";

    g.set_wanted([](string s) { return s[3] == 'm';});
    const auto g2=g;
    // Should only get gamma and sigma:
    for (auto s : g2)
        cout << "m: " << s << "\n";

    Game::iterator it = g2.begin();
    assert(it == g2.begin());
    assert(!(it != g2.begin()));
    assert(it != g2.end());
    assert(!(it == g2.end()));
    assert(g2.begin() != g2.end());
    assert(*it == "gamma");
    assert(*it == "gamma");
    assert(*it != "YMP");
    assert(!(*it == "ffff"));
    auto it2 = it++;
    assert(*it2 == "gamma");
    assert(*it == "sigma");
    it2 = ++it;
    assert(it2 == it);
    assert(it == g2.end());

    cout << "Done!\n";

    return 0;
}
% ./test
all: alpha
all: gamma
all: delta
all: theta
all: kappa
all: sigma
all: omega
no e: alpha
no e: gamma
no e: kappa
no e: sigma
m: gamma
m: sigma
Done!

Requirements                

• All requirements from HW5 apply.
• The words must come out of an iterator in the same order that they were added by .add_dict, and in the order inside each file.
• The words, matching or not, must exist only once in memory, in a container in the Game object. Your iterator must not copy all of the words, or even just the matching words, into another vector, array, or any other container. Each word must exist only once in the Game object itself, with only a single word or two copied to individual scalars.
• It must be an compile-time error or warning to ignore the return value of .begin() or .end(), or the value from * applied to a Game::iterator.
• An iterator is invalidated if the associated Game object:
  • has .add_dict() or .set_wanted() called
  • falls out of scope
  • is overwritten by assignment
• Undefined behavior results if:
  • .set_length() is called after .add_dict()
  • * is applied to an .end() iterator
  • an iterator is incremented past the .end() value
  • an uninitialized iterator is used in any way except assigning to it
  • an invalidated iterator is used.
• More than one iterator can be associated with a Game object at the same time. The iterators have independent positions.

Tar file                

• The tar file for this assignment must be called: hw7.tar
• It must contain:
  • source files (*.cc), including Game.cc
  • header files (*.h), including Game.h
  • CMakeLists.txt, which will create the library file libhw7.a.
• These commands must produce the library libhw7.a:

    cmake . && make

• Your CMakeLists.txt must use at least -Wall when compiling.

How to submit your work:                

In Canvas, check in the file hw7.tar to the assignment “HW7”. It’s due 11:59ᴘᴍ MT Saturday, with a 24-hour late period for a 25% penalty.                 

How to receive negative points:                

Turn in someone else’s work.