C++ numbers

cpp/README.md

@@ -18,3 +18,4 @@
 - [last-will](./last-will/README.md)
 - [log-levels](./log-levels/README.md)
 - [raindrops](./raindrops/README.md)
+- [freelancer-rates](./freelancer-rates/README.md)

cpp/freelancer-rates/.exercism/config.json

@@ -0,0 +1,21 @@
+{
+  "authors": [
+    "vaeng"
+  ],
+  "files": {
+    "solution": [
+      "freelancer_rates.cpp"
+    ],
+    "test": [
+      "freelancer_rates_test.cpp"
+    ],
+    "exemplar": [
+      ".meta/exemplar.cpp"
+    ]
+  },
+  "forked_from": [
+    "elixir/freelancer-rates"
+  ],
+  "icon": "freelancer-rates",
+  "blurb": "Learn about integers and floating point numbers by helping a freelancer communicate with a project manager about billing."
+}

cpp/freelancer-rates/.exercism/metadata.json

@@ -0,0 +1 @@
+{"track":"cpp","exercise":"freelancer-rates","id":"f65aae8584e743e4a95c7f3a0dd0fd63","url":"https://exercism.org/tracks/cpp/exercises/freelancer-rates","handle":"vpayno","is_requester":true,"auto_approve":false}

cpp/freelancer-rates/CMakeLists.txt

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+# Basic CMake project
+cmake_minimum_required(VERSION 3.5.1)
+
+# Get the exercise name from the current directory
+get_filename_component(exercise ${CMAKE_CURRENT_SOURCE_DIR} NAME)
+
+# Name the project after the exercise
+project(${exercise} CXX)
+
+# 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 ${file}.cpp)
+else()
+  set(exercise_cpp "")
+endif()
+
+# Use the common Catch library?
+if(EXERCISM_COMMON_CATCH)
+  # For Exercism track development only
+  add_executable(${exercise} ${file}_test.cpp $<TARGET_OBJECTS:catchlib>)
+elseif(EXERCISM_TEST_SUITE)
+  # The Exercism test suite is being run, the Docker image already includes a
+  # pre-built version of Catch.
+  find_package(Catch2 REQUIRED)
+  add_executable(${exercise} ${file}_test.cpp)
+  target_link_libraries(${exercise} PRIVATE Catch2::Catch2WithMain)
+  # When Catch is installed system wide we need to include a different header,
+  # we need this define to use the correct one.
+  target_compile_definitions(${exercise} PRIVATE EXERCISM_TEST_SUITE)
+else()
+  # Build executable from sources and headers
+  add_executable(${exercise} ${file}_test.cpp test/tests-main.cpp)
+endif()
+
+set_target_properties(
+  ${exercise}
+  PROPERTIES CXX_STANDARD 17
+             CXX_STANDARD_REQUIRED OFF
+             CXX_EXTENSIONS OFF)
+
+set(CMAKE_BUILD_TYPE Debug)
+
+if("${CMAKE_CXX_COMPILER_ID}" MATCHES "(GNU|Clang)")
+  set_target_properties(
+    ${exercise} PROPERTIES COMPILE_FLAGS "-Wall -Wextra -Wpedantic -Werror")
+endif()
+
+# Configure to run all the tests?
+if(${EXERCISM_RUN_ALL_TESTS})
+  target_compile_definitions(${exercise} PRIVATE EXERCISM_RUN_ALL_TESTS)
+endif()
+
+# Tell MSVC not to warn us about unchecked iterators in debug builds
+if(${MSVC})
+  set_target_properties(${exercise} PROPERTIES COMPILE_DEFINITIONS_DEBUG
+                                               _SCL_SECURE_NO_WARNINGS)
+endif()
+
+# Run the tests on every build
+add_custom_target(
+  test_${exercise} ALL
+  DEPENDS ${exercise}
+  COMMAND ${exercise})

cpp/freelancer-rates/HELP.md

@@ -0,0 +1,55 @@
+# Help
+
+## Running the tests
+
+Running the tests involves running `cmake -G` and then using the build command appropriate for your platform.
+Detailed instructions on how to do this can be found on the [Running the Tests](https://exercism.io/tracks/cpp/tests) page for C++ on exercism.io.
+
+## 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.
+
+## Submitting your solution
+
+You can submit your solution using the `exercism submit freelancer_rates.cpp` command.
+This command will upload your solution to the Exercism website and print the solution page's URL.
+
+It's possible to submit an incomplete solution which allows you to:
+
+- See how others have completed the exercise
+- Request help from a mentor
+
+## Need to get help?
+
+If you'd like help solving the exercise, check the following pages:
+
+- The [C++ track's documentation](https://exercism.org/docs/tracks/cpp)
+- [Exercism's programming category on the forum](https://forum.exercism.org/c/programming/5)
+- The [Frequently Asked Questions](https://exercism.org/docs/using/faqs)
+
+Should those resources not suffice, you could submit your (incomplete) solution to request mentoring.
+
+To get help if you're having trouble, you can use one of the following resources:
+
+- [`c++-faq` tag on StackOverflow](https://stackoverflow.com/tags/c%2b%2b-faq/info)
+- [C++ FAQ from isocpp.com](https://isocpp.org/faq)
+- [CppReference](http://en.cppreference.com/) is a wiki reference to the C++ language and standard library
+- [C traps and pitfalls](http://www.slideshare.net/LegalizeAdulthood/c-traps-and-pitfalls-for-c-programmers) is useful if you are new to C++, but have programmed in C

cpp/freelancer-rates/HINTS.md

@@ -0,0 +1,24 @@
+# Hints
+
+## General
+
+- Browse the [`cmath` reference][cmath-reference] to learn about common mathematical operations and transformations that work with `doubles`.
+
+## 1. Calculate the daily rate given an hourly rate
+
+- Basic arithmetic operations where one argument is an `int`, and the other is a `double`, will return a `double`.
+
+## 2. Calculate a discounted price
+
+- Basic arithmetic operations where one argument is an `int`, and the other is a `double`, will return a `double`.
+
+## 3. Calculate the monthly rate, given an hourly rate and a discount
+
+- There is a [function in the `cmath` header][cmath-ceil] for rounding up.
+
+## 4. Calculate the number of workdays given a budget, hourly rate, and discount
+
+- Casting a `double` to an `int` will truncate the number at the decimal point.
+
+[cmath-reference]: https://en.cppreference.com/w/cpp/header/cmath
+[cmath-ceil]: https://en.cppreference.com/w/cpp/numeric/math/ceil

cpp/freelancer-rates/Makefile

@@ -0,0 +1,23 @@
+.PHONY: clean
+clean:
+	rm -rf ./build
+
+.PHONY: test
+test: clean
+	mkdir -pv ./build
+
+	@printf "\n"
+	@# each line is executed in a subshell, we have to daisy chain them so they
+	@# run in the build directory
+	cd ./build; export LDFLAGS="-lgcov --coverage" CXXFLAGS="--coverage"; cmake -DEXERCISM_RUN_ALL_TESTS=1 -DCMAKE_EXPORT_COMPILE_COMMANDS=1 -G 'Unix Makefiles' ../; if make; then printf "\n=== All Tests Passed ===\n"; else printf "\n=== Test Failure ===\n"; false; fi
+
+.PHONY: coverage
+coverage: test
+	@printf "\n"
+	find . -regextype posix-egrep -regex "^.*(tests-main|CompilerId).*[.](gcda|gcno)$$" -print -delete
+
+	@printf "\n"
+	find . -regextype posix-egrep -regex "^.*[.](gcda|gcno)17040"
+
+	@printf "\n"
+	gcovr --print-summary

cpp/freelancer-rates/README.md

@@ -0,0 +1,124 @@
+# Freelancer Rates
+
+Welcome to Freelancer Rates on Exercism's C++ Track.
+If you need help running the tests or submitting your code, check out `HELP.md`.
+If you get stuck on the exercise, check out `HINTS.md`, but try and solve it without using those first :)
+
+## Introduction
+
+## Numbers
+
+The built-in number types in C++ can be divided into integers and floating points.
+Integers are whole numbers like `0`, `691`, or `-2`.
+Floating point numbers are numbers with a decimal point like `6.02214076`, `0.1`, or `-1.616`.
+
+### Integers
+
+The following example shows the declaration and initialization of four different variables:
+
+```cpp
+int m_morales{9241};              // base 10: 0-9
+int a_apaec{0x24CD};              // base 16: 0-9 and A-F
+int m_gargan{0b10010000011001};   // base  2: 0-1
+int b_reilly{022031};             // base  8: 0-7
+                                  // Leading with a 0 not the letter o.
+```
+
+When you assign a value to an `int` variable, you can do so directly with a literal.
+A literal is a hard-coded number like `9241`.
+There are different integer literals for several bases of the representation.
+Decimal integer literals are the most common and use the digits `0` to `9`.
+By adding a special prefix, like `0x`, it is possible to use other bases.
+The example above shows the number `9421` in its four representations and prefixes.
+All variables are initialized to the same value.
+
+For more details on the different representation systems, take a look at [a small tutorial][cpp_numerical_bases].
+
+You can use an apostrophe to separate digits for easier readability.
+`9'241` is the same as `0b0100'100'0001'1001` or `92'4'1`.
+
+### Floating-Point Numbers
+
+The floating-point literals come in two flavors.
+In addition to the intuitive `0.0024` it is possible to use its scientific notation `2.4e-3`.
+The most common floating-point type is `double`.
+
+### Arithmetic
+
+C++ supports `+`, `-`, `*`, `/`, `(` and `)` and `%` to form expressions.
+The result from the operation between two integers is also an integer.
+`5 / 2` will return `2`.
+When one of the involved types is a floating-point type, the result will also be of a floating-point.
+`5.0 / 2` and `5 / 2.0` will return `2.5`.
+`%` is the remainder operator and will return the remainder of an integer division: `5%3` is `2`.
+
+[cpp_numerical_bases]: https://cplusplus.com/doc/hex/
+
+## Instructions
+
+In this exercise, you'll be writing code to help a freelancer communicate with a project manager.
+Your task is to provide a few utilities to quickly calculate daily and monthly rates, optionally with a given discount.
+
+We first establish a few rules between the freelancer and the project manager:
+
+- The daily rate is 8 times the hourly rate.
+- A month has 22 billable days.
+
+Sometimes, the freelancer is offering to apply a discount on their daily rate (for example for their most loyal customers or not-for-profit customers).
+
+Discounts are modeled as fractional numbers representing percentages, for example, `25.0` (25%).
+
+## 1. Calculate the daily rate given an hourly rate
+
+Implement a function to calculate the daily rate given an hourly rate:
+
+```cpp
+daily_rate(60)
+// => 480.0
+```
+
+The returned daily rate should be of type `double`.
+
+## 2. Calculate a discounted price
+
+Implement a function to calculate the price after a discount.
+
+```cpp
+apply_discount(150, 10)
+// => 135.0
+```
+
+The returned value should always be of type `double`, not rounded in any way.
+
+## 3. Calculate the monthly rate, given an hourly rate and a discount
+
+Implement a function to calculate the monthly rate, and apply a discount.
+
+```cpp
+monthly_rate(77, 10.5)
+// => 12130
+```
+
+The returned monthly rate should be rounded up (take the ceiling) to the nearest integer.
+
+## 4. Calculate the number of complete workdays given a budget, hourly rate, and discount
+
+Implement a function that takes a budget, an hourly rate, and a discount, and calculates how many complete days of work that covers.
+
+```cpp
+days_in_budget(20'000, 80, 11.0)
+// => 35
+```
+
+The returned number of days should be rounded down (take the floor) to the next integer.
+
+## Source
+
+### Created by
+
+- @vaeng
+
+### My Solution
+
+- [my solution]()
+- [run-tests](./run-tests-cpp.txt)

cpp/freelancer-rates/compile_commands.json

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+[
+{
+  "directory": "/home/vpayno/git_vpayno/exercism-workspace/cpp/freelancer-rates/build",
+  "command": "/usr/bin/c++ -DEXERCISM_RUN_ALL_TESTS  --coverage -g -Wall -Wextra -Wpedantic -Werror -std=c++17 -o CMakeFiles/freelancer-rates.dir/freelancer_rates_test.cpp.o -c /home/vpayno/git_vpayno/exercism-workspace/cpp/freelancer-rates/freelancer_rates_test.cpp",
+  "file": "/home/vpayno/git_vpayno/exercism-workspace/cpp/freelancer-rates/freelancer_rates_test.cpp"
+},
+{
+  "directory": "/home/vpayno/git_vpayno/exercism-workspace/cpp/freelancer-rates/build",
+  "command": "/usr/bin/c++ -DEXERCISM_RUN_ALL_TESTS  --coverage -g -Wall -Wextra -Wpedantic -Werror -std=c++17 -o CMakeFiles/freelancer-rates.dir/test/tests-main.cpp.o -c /home/vpayno/git_vpayno/exercism-workspace/cpp/freelancer-rates/test/tests-main.cpp",
+  "file": "/home/vpayno/git_vpayno/exercism-workspace/cpp/freelancer-rates/test/tests-main.cpp"
+}
+]

cpp/freelancer-rates/compile_flags.txt

@@ -0,0 +1,8 @@
+-std=c++17
+-stdlib=libstdc++
+-g
+-Wall
+-Wextra
+-Wpedantic
+-Werror
+-Wno-unused-parameter

cpp/freelancer-rates/freelancer_rates.cpp

@@ -0,0 +1,40 @@
+#include <cmath>
+
+// daily_rate calculates the daily rate given an hourly rate
+double daily_rate(double hourly_rate) {
+    const double hours = 8.0;
+
+    return hours * hourly_rate;
+}
+
+// apply_discount calculates the price after a discount
+double apply_discount(double before_discount, double discount) {
+    const double charge_rate = (100 - discount) / 100;
+
+    return before_discount * charge_rate;
+}
+
+// monthly_rate calculates the monthly rate, given an hourly rate and a discount
+// The returned monthly rate is rounded up to the nearest integer.
+int monthly_rate(double hourly_rate, double discount) {
+    const double billable_days = 22.0;
+
+    const double monthly_cost = daily_rate(hourly_rate) * billable_days;
+
+    const double discounted_cost = apply_discount(monthly_cost, discount);
+
+    return std::ceil(discounted_cost);
+}
+
+// days_in_budget calculates the number of workdays given a budget, hourly rate,
+// and discount The returned number of days is rounded down (take the floor) to
+// the next integer.
+int days_in_budget(int budget, double hourly_rate, double discount) {
+    const double daily_cost = daily_rate(hourly_rate);
+
+    const double discounted_hourly = apply_discount(daily_cost, discount);
+
+    const double days = budget / std::ceil(discounted_hourly);
+
+    return std::floor(days);
+}