prime_factors: initial commit

cpp/prime-factors/CMakeLists.txt

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+# Get the exercise name from the current directory
+get_filename_component(exercise ${CMAKE_CURRENT_SOURCE_DIR} NAME)
+
+# Basic CMake project
+cmake_minimum_required(VERSION 2.8.11)
+
+# Name the project after the exercise
+project(${exercise} CXX)
+
+# Locate Boost libraries: unit_test_framework, date_time and regex
+set(Boost_USE_STATIC_LIBS ON)
+set(Boost_USE_MULTITHREADED ON)
+set(Boost_USE_STATIC_RUNTIME OFF)
+find_package(Boost 1.55 REQUIRED COMPONENTS unit_test_framework date_time regex)
+
+# Enable C++11 features on gcc/clang
+if("${CMAKE_CXX_COMPILER_ID}" MATCHES "(GNU|Clang)")
+    set(CMAKE_CXX_FLAGS "-std=c++11")
+endif()
+
+# Configure to run all the tests?
+if(${EXERCISM_RUN_ALL_TESTS})
+    add_definitions(-DEXERCISM_RUN_ALL_TESTS)
+endif()
+
+# Get a source filename from the exercise name by replacing -'s with _'s
+string(REPLACE "-" "_" file ${exercise})
+
+# Implementation could be only a header
+if(EXISTS ${CMAKE_CURRENT_SOURCE_DIR}/${file}.cpp)
+    set(exercise_cpp ${file}.cpp)
+else()
+    set(exercise_cpp "")
+endif()
+
+# Include a test helper header if it exists
+if(EXISTS ${CMAKE_CURRENT_SOURCE_DIR}/require_equal_containers.h)
+    set(test_helper require_equal_containers.h)
+else()
+    set(test_helper "")
+endif()
+
+# Build executable from sources and headers
+add_executable(${exercise} ${file}_test.cpp ${test_helper} ${exercise_cpp} ${file}.h)
+
+# We need boost includes
+target_include_directories(${exercise} PRIVATE ${Boost_INCLUDE_DIRS})
+
+# We need boost libraries
+target_link_libraries(${exercise} ${Boost_LIBRARIES})
+
+# Tell MSVC not to warn us about unchecked iterators in debug builds
+if(${MSVC})
+    set_target_properties(${exercise} PROPERTIES
+        COMPILE_DEFINITIONS_DEBUG _SCL_SECURE_NO_WARNINGS)
+endif()
+
+# Run the tests on every build
+add_custom_command(TARGET ${exercise} POST_BUILD COMMAND ${exercise})

cpp/prime-factors/README.md

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+# Prime Factors
+
+Compute the prime factors of a given natural number.
+
+A prime number is only evenly divisible by itself and 1.
+
+Note that 1 is not a prime number.
+
+## Example
+
+What are the prime factors of 60?
+
+- Our first divisor is 2. 2 goes into 60, leaving 30.
+- 2 goes into 30, leaving 15.
+  - 2 doesn't go cleanly into 15. So let's move on to our next divisor, 3.
+- 3 goes cleanly into 15, leaving 5.
+  - 3 does not go cleanly into 5. The next possible factor is 4.
+  - 4 does not go cleanly into 5. The next possible factor is 5.
+- 5 does go cleanly into 5.
+- We're left only with 1, so now, we're done.
+
+Our successful divisors in that computation represent the list of prime
+factors of 60: 2, 2, 3, and 5.
+
+You can check this yourself:
+
+- 2 * 2 * 3 * 5
+- = 4 * 15
+- = 60
+- Success!
+
+## Getting Started
+
+Make sure you have read [the C++ page](http://exercism.io/languages/cpp) on
+exercism.io.  This covers the basic information on setting up the development
+environment expected by the exercises.
+
+## Passing the Tests
+
+Get the first test compiling, linking and passing by following the [three
+rules of test-driven development](http://butunclebob.com/ArticleS.UncleBob.TheThreeRulesOfTdd).
+Create just enough structure by declaring namespaces, functions, classes,
+etc., to satisfy any compiler errors and get the test to fail.  Then write
+just enough code to get the test to pass.  Once you've done that,
+uncomment the next test by moving the following line past the next test.
+
+```C++
+#if defined(EXERCISM_RUN_ALL_TESTS)
+```
+
+This may result in compile errors as new constructs may be invoked that
+you haven't yet declared or defined.  Again, fix the compile errors minimally
+to get a failing test, then change the code minimally to pass the test,
+refactor your implementation for readability and expressiveness and then
+go on to the next test.
+
+Try to use standard C++11 facilities in preference to writing your own
+low-level algorithms or facilities by hand.  [CppReference](http://en.cppreference.com/)
+is a wiki reference to the C++ language and standard library.  If you
+are new to C++, but have programmed in C, beware of
+[C traps and pitfalls](http://www.slideshare.net/LegalizeAdulthood/c-traps-and-pitfalls-for-c-programmers).
+
+## Source
+
+The Prime Factors Kata by Uncle Bob [view source](http://butunclebob.com/ArticleS.UncleBob.ThePrimeFactorsKata)

cpp/prime-factors/prime_factors_test.cpp

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+#include "prime_factors.h"
+#define BOOST_TEST_MAIN
+#include <boost/test/unit_test.hpp>
+
+BOOST_AUTO_TEST_CASE(_1_yields_empty)
+{
+    const std::vector<int> expected{};
+
+    const std::vector<int> actual{prime_factors::of(1)};
+
+    BOOST_REQUIRE_EQUAL_COLLECTIONS(expected.begin(), expected.end(), actual.begin(), actual.end());
+}
+
+#if defined(EXERCISM_RUN_ALL_TESTS)
+BOOST_AUTO_TEST_CASE(_2_yields_2)
+{
+    const std::vector<int> expected{2};
+
+    const std::vector<int> actual{prime_factors::of(2)};
+
+    BOOST_REQUIRE_EQUAL_COLLECTIONS(expected.begin(), expected.end(), actual.begin(), actual.end());
+}
+
+BOOST_AUTO_TEST_CASE(_3_yields_3)
+{
+    const std::vector<int> expected{3};
+
+    const std::vector<int> actual{prime_factors::of(3)};
+
+    BOOST_REQUIRE_EQUAL_COLLECTIONS(expected.begin(), expected.end(), actual.begin(), actual.end());
+}
+
+BOOST_AUTO_TEST_CASE(_4_yields_2_2)
+{
+    const std::vector<int> expected{2, 2};
+
+    const std::vector<int> actual{prime_factors::of(4)};
+
+    BOOST_REQUIRE_EQUAL_COLLECTIONS(expected.begin(), expected.end(), actual.begin(), actual.end());
+}
+
+BOOST_AUTO_TEST_CASE(_6_yields_2_3)
+{
+    const std::vector<int> expected{2, 3};
+
+    const std::vector<int> actual{prime_factors::of(6)};
+
+    BOOST_REQUIRE_EQUAL_COLLECTIONS(expected.begin(), expected.end(), actual.begin(), actual.end());
+}
+
+BOOST_AUTO_TEST_CASE(_8_yields_2_2_2)
+{
+    const std::vector<int> expected{2, 2, 2};
+
+    const std::vector<int> actual{prime_factors::of(8)};
+
+    BOOST_REQUIRE_EQUAL_COLLECTIONS(expected.begin(), expected.end(), actual.begin(), actual.end());
+}
+
+BOOST_AUTO_TEST_CASE(_9_yields_3_3)
+{
+    const std::vector<int> expected{3, 3};
+
+    const std::vector<int> actual{prime_factors::of(9)};
+
+    BOOST_REQUIRE_EQUAL_COLLECTIONS(expected.begin(), expected.end(), actual.begin(), actual.end());
+}
+
+BOOST_AUTO_TEST_CASE(_27_yields_3_3_3)
+{
+    const std::vector<int> expected{3, 3, 3};
+
+    const std::vector<int> actual{prime_factors::of(27)};
+
+    BOOST_REQUIRE_EQUAL_COLLECTIONS(expected.begin(), expected.end(), actual.begin(), actual.end());
+}
+
+BOOST_AUTO_TEST_CASE(_625_yields_5_5_5_5)
+{
+    const std::vector<int> expected{5, 5, 5, 5};
+
+    const std::vector<int> actual{prime_factors::of(625)};
+
+    BOOST_REQUIRE_EQUAL_COLLECTIONS(expected.begin(), expected.end(), actual.begin(), actual.end());
+}
+
+BOOST_AUTO_TEST_CASE(_901255_yields_5_17_23_461)
+{
+    const std::vector<int> expected{5, 17, 23, 461};
+
+    const std::vector<int> actual{prime_factors::of(901255)};
+
+    BOOST_REQUIRE_EQUAL_COLLECTIONS(expected.begin(), expected.end(), actual.begin(), actual.end());
+}
+#endif