CS253 HW7: Iteration!

Description

For this assignment, you will build upon your previous work in HW6.

Your Gallery class now works with the for (auto v : container) syntax! This implies support for Gallery::begin(), Gallery::end(), and Gallery::iterator. Looping over a Gallery produces read-only references to Enemies, in an unspecified (but complete) order.

Similarly, the Enemy class now works with for (auto v : container), so you need Enemy::begin(), Enemy::end(), and Enemy::iterator. Looping over a Enemy produces read-only pairs, containing, in order, the corresponding key & value, much like Enemy[size_t]. The pairs are returned in an unspecified (but complete) order.

Methods

New `Gallery` methods

The following methods & operators must work, where git is of type Gallery::iterator.

Gallery::begin()

Returns an object of type Gallery::iterator that corresponds to the first Enemy in the Gallery.

Gallery::end()

Returns an object of type Gallery::iterator that corresponds to one past the last Enemy in the Gallery.
Past, I say! It does not correspond to the last item, since begin() & end() form a half-open interval.

++git

git++

--git

git--

Increments or decrements the iterator.
Preincrement/predecrement return the new value, and postincrement/postdecrement return the previous value, in the same manner as ++ and -- work on integers.

*git

Yields a const reference to the Enemy associated with the iterator.

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.

New `Enemy` methods

The following methods & operators must work, where eit is of type Enemy::iterator.

Enemy::begin()

Returns an object of type Enemy::iterator that corresponds to the first key,value pair in the Enemy.

Enemy::end()

Returns an object of type Enemy::iterator that corresponds to one past the last key,value pair in the Enemy.
Past, I say! It does not correspond to the last item, since begin() & end() form a half-open interval.

++eit

eit++

--eit

eit--

Increments or decrements the iterator.
Preincrement/predecrement return the new value, and postincrement/postdecrement return the previous value, in the same manner as ++ and -- work on integers.

*eit

Yields the the corresponding pair containing the key,value associated with the iterator. This pair may be returned by value or const reference.

eit == eit

eit != eit

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

copy, assignment

Iterators are copy-constructable, and assignable.

Const-correctness is your job for all new methods & operators.

Lifetime

Altering a Gallery or an Enemy potentially invalidates the corresponding iterators.

Debugging

If you encounter “STACK FRAME LINK OVERFLOW”, then try this:

    export STACK_FRAME_LINK_OVERRIDE=ffff-ad921d60486366258809553a3db49a4a

Sample Run

This focuses on the features added in this assignment. This does not imply that the previous features are abandoned.

% cat CMakeLists.txt
cmake_minimum_required(VERSION 3.14)

# 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)
add_compile_options(-fstack-protector-all -g -O3 -std=c++14 -Walloc-zero)
add_compile_options(-Walloca -Wctor-dtor-privacy -Wduplicated-cond)
add_compile_options(-Wduplicated-branches -Werror -Wfatal-errors -Winit-self)
add_compile_options(-Wlogical-op -Wold-style-cast -Wshadow)
add_compile_options(-Wunused-const-variable=1 -Wzero-as-null-pointer-constant)

# add_compile_options must be BEFORE add_executable or add_library.

add_library(hw7 Enemy.cc Keys.cc Gallery.cc)
add_executable(test test.cc)
target_link_libraries(test hw7)

# Create a tar file every time:
add_custom_target(hw7.tar ALL COMMAND tar cf hw7.tar *.cc *.h CMakeLists.txt)
% cat oz-villains



Title    Wicked Witch of the West
Name     Elphaba
Where    Winkie Country (west)
Origin   The Wonderful Wizard of Oz (1900)
img      https://upload.wikimedia.org/wikipedia/commons/9/93/Wicked_Witch_of_the_West.png

Title    Nome King
Title2   Gnome King
Where    Underground
Name     Roquat the Red
Name2    Ruggedo
Origin   Ozma of Oz (1907)
img      https://upload.wikimedia.org/wikipedia/commons/f/fb/I212.jpg?2097151


Name     Mombi
Title    Wicked Witch of the North
Where    Gillikin Country (north)
Origin   The Marvelous Land of Oz (1904)
img      http://www.oztimeline.net/mombi%20neill%202.gif




% cat oz-keys
Name
Name2
Where
Title
Title2
Origin
img
Alias
% cat test.cc
#include "Gallery.h"
#include <algorithm>
#include <cassert>
#include <iostream>
#include <string>
#include <stdexcept>

using namespace std;

void show(const Enemy e) {          // pass by value to force a copy
    for (auto p : e) {
        assert(e[p.first] == p.second);
        cout << p.first << ": " << p.second << '\n';
    }
}

void show(const Gallery g) {        // pass by value to force a copy
    string gutter;
    for (const Enemy &e : g) {
        cout << gutter;
        gutter = "\n";
        show(e);
    }
}

void test_comparison_operators(const Gallery &g) {
    assert(g.size() >= 3);

    assert(g[0] == g[0]);
    assert(g[1] == g[1]);
    assert(!(g[1] == g[0]));
    assert(!(g[0] == g[1]));

    assert(!(g[0] != g[0]));
    assert(!(g[1] != g[1]));
    assert(g[1] != g[0]);
    assert(g[0] != g[1]);

    // Guarantee that all Enemies in this Gallery are distinct.
    assert(g[0] != g[2]);
    assert(g[1] != g[2]);
}

void test_gallery_iterators(const Gallery &g) {
    Gallery::iterator it1 = g.begin();
    auto a1 = it1++;            // iterator “pointing” to first element
    auto b1 = it1++;            // iterator “pointing” to second element
    auto c1 = it1++;            // iterator “pointing” to third element

    Gallery::iterator it2 = g.begin();
    const auto a2 = it2;        // iterator “pointing” to first element
    const auto b2 = ++it2;      // iterator “pointing” to second element
    const auto c2 = ++it2;      // iterator “pointing” to third element

    Gallery::iterator it3 = g.end();
    const auto c3 = --it3;      // iterator “pointing” to third element
    const auto b3 = --it3;      // iterator “pointing” to second element
    const auto a3 = --it3;      // iterator “pointing” to first element

    Gallery::iterator it4 = g.end();
    it4--;                      // now “points” to third element
    auto c4 = it4--;            // iterator “pointing” to third element
    auto b4 = it4--;            // iterator “pointing” to second element
    auto a4 = it4;              // iterator “pointing” to first element

    // All three must be distinct.
    assert(a1 != b1);
    assert(a1 != c1);
    assert(b1 != c1);

    // Assure that the iterators, acquired in various ways, match.
    assert(a1 == a2);
    assert(b1 == b2);
    assert(c1 == c2);

    assert(a1 == a3);
    assert(b1 == b3);
    assert(c1 == c3);

    assert(a1 == a4);
    assert(b1 == b4);
    assert(c1 == c4);

    // Instead of comparing iterators, now compare Enemies.
    assert(*a1 != *b1);
    assert(*a1 != *c1);
    assert(*b1 != *c1);

    assert(*a1 == *a2);
    assert(*b1 == *b2);
    assert(*c1 == *c2);

    assert(*a1 == *a3);
    assert(*b1 == *b3);
    assert(*c1 == *c3);

    assert(*a1 == *a4);
    assert(*b1 == *b4);
    assert(*c1 == *c4);
}

void test_enemy_iterators(const Gallery &g) {
    // Find an Enemy in this Gallery with five key/value pairs:
    const Enemy &e = g[0].size()==5 ? g[0] : g[1];
    assert(e.size() == 5);

    Enemy::iterator it1 = e.begin();
    auto a1 = it1++;            // iterator “pointing” to first element
    auto b1 = it1++;            // iterator “pointing” to second element
    auto c1 = it1++;            // iterator “pointing” to third element

    Enemy::iterator it2 = e.begin();
    const auto a2 = it2;        // iterator “pointing” to first element
    const auto b2 = ++it2;      // iterator “pointing” to second element
    const auto c2 = ++it2;      // iterator “pointing” to third element

    Enemy::iterator it3 = e.end();
    it3--; --it3;               // now “points” to fourth element
    const auto c3 = --it3;      // iterator “pointing” to third element
    const auto b3 = --it3;      // iterator “pointing” to second element
    const auto a3 = --it3;      // iterator “pointing” to first element

    Enemy::iterator it4 = e.end();
    --it4; it4--; --it4;        // now “points” to third element
    auto c4 = it4--;            // iterator “pointing” to third element
    auto b4 = it4--;            // iterator “pointing” to second element
    auto a4 = it4;              // iterator “pointing” to first element

    // All three must be distinct.
    assert(a1 != b1);
    assert(a1 != c1);
    assert(b1 != c1);

    // Assure that the iterators, acquired in various ways, match.
    assert(a1 == a2);
    assert(b1 == b2);
    assert(c1 == c2);

    assert(a1 == a3);
    assert(b1 == b3);
    assert(c1 == c3);

    assert(a1 == a4);
    assert(b1 == b4);
    assert(c1 == c4);

    // Instead of comparing iterators, now compare key/value pairs.
    assert(*a1 != *b1);
    assert(*a1 != *c1);
    assert(*b1 != *c1);

    assert(*a1 == *a2);
    assert(*b1 == *b2);
    assert(*c1 == *c2);

    assert(*a1 == *a3);
    assert(*b1 == *b3);
    assert(*c1 == *c3);

    assert(*a1 == *a4);
    assert(*b1 == *b4);
    assert(*c1 == *c4);
}

int main() {
    try {
        const Gallery vacant("oz-keys", "/dev/null");
        Gallery monsters("oz-villains", "oz-keys");

        assert(!vacant);
        assert(monsters);
        assert(monsters[0]);

        test_comparison_operators(monsters);
        test_gallery_iterators(monsters);
        test_enemy_iterators(monsters);

        show(vacant);
        show(monsters);
    }
    catch (const exception &e) {
        cerr << "Unexpected exception: " << e.what() << '\n';
        return 1;
    }
    catch (...) {
        cerr << "Caught something, but it’s not a std::exception‽\n";
        return 2;
    }

    cout << "*** Done! ***\n";

    return 0;
}
% cmake .
… cmake output appears here …
% make
… make output appears here …
[100%] Built target test
% ./test
Name: Elphaba
Origin: The Wonderful Wizard of Oz (1900)
Title: Wicked Witch of the West
Where: Winkie Country (west)
img: https://upload.wikimedia.org/wikipedia/commons/9/93/Wicked_Witch_of_the_West.png

Title2: Gnome King
Title: Nome King
Origin: Ozma of Oz (1907)
Name: Roquat the Red
Name2: Ruggedo
Where: Underground
img: https://upload.wikimedia.org/wikipedia/commons/f/fb/I212.jpg?2097151

Where: Gillikin Country (north)
Name: Mombi
Origin: The Marvelous Land of Oz (1904)
Title: Wicked Witch of the North
img: http://www.oztimeline.net/mombi%20neill%202.gif
*** Done! ***

Requirements

Same as the previous assignment, given the additional features above.

Tar file

The tar file for this assignment must be called: hw7.tar
It must contain:
- source files (*.cc), including Enemy.cc and Gallery.cc
- header files (*.h), including Enemy.h and Gallery.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 homework:

Use web checkin, or Linux checkin:

    ~cs253/bin/checkin HW7 hw7.tar

How to receive negative points:

Turn in someone else’s work.

CS253: Software Development with C++

Fall 2019

HW 7

CS253 HW7: Iteration!

Description

Methods

New `Gallery` methods

New `Enemy` methods

Lifetime

Debugging

Sample Run

Requirements

Tar file

How to submit your homework:

How to receive negative points:

CS253 HW7: Iteration!

Description

Methods

New Gallery methods

New Enemy methods

Lifetime

Debugging

Sample Run

Requirements

Tar file

How to submit your homework:

How to receive negative points:

New `Gallery` methods

New `Enemy` methods