feat: add pop-count practice exercise

config.json

@@ -1009,6 +1009,21 @@
         "difficulty": 4,
         "topics": [
         ]
+      },
+      {
+        "slug": "pop-count",
+        "name": "Pop Count",
+        "uuid": "cfe01bad-0972-466c-b52a-9b8cf563b2f4",
+        "practices": [
+          "loops"
+        ],
+        "prerequisites": [
+          "if-statements",
+          "comparisons"
+        ],
+        "difficulty": 3,
+        "topics": [
+        ]
       }
     ],
     "foregone": [

exercises/practice/pop-count/.docs/instructions.md

@@ -0,0 +1,8 @@
+# Instructions
+
+Your task is to count the number of 1 bits in the binary representation of a number.
+
+## Restrictions
+
+Keep your hands off that bit-count functionality provided by your standard library!
+Solve this one yourself using other basic tools instead.

exercises/practice/pop-count/.docs/introduction.md

@@ -0,0 +1,47 @@
+# Introduction
+
+Your friend Eliud inherited a farm from her grandma Tigist.
+Her granny was an inventor and had a tendency to build things in an overly complicated manner.
+The chicken coop has a digital display showing an encoded number representing the positions of all eggs that could be picked up.
+
+Eliud is asking you to write a program that shows the actual number of eggs in the coop.
+
+The position information encoding is calculated as follows:
+
+1. Scan the potential egg-laying spots and mark down a `1` for an existing egg or a `0` for an empty spot.
+2. Convert the number from binary to decimal.
+3. Show the result on the display.
+
+Example 1:
+
+```text
+Chicken Coop:
+ _ _ _ _ _ _ _
+|E| |E|E| | |E|
+
+Resulting Binary:
+ 1 0 1 1 0 0 1
+
+Decimal number on the display:
+89
+
+Actual eggs in the coop:
+4
+```
+
+Example 2:
+
+```text
+Chicken Coop:
+ _ _ _ _ _ _ _ _
+| | | |E| | | | |
+
+Resulting Binary:
+ 0 0 0 1 0 0 0 0
+
+Decimal number on the display:
+16
+
+Actual eggs in the coop:
+1
+```

exercises/practice/pop-count/.meta/config.json

@@ -0,0 +1,22 @@
+{
+  "authors": [
+    "vaeng"
+  ],
+  "contributors": [],
+  "files": {
+    "solution": [
+      "pop_count.cpp",
+      "pop_count.h"
+    ],
+    "test": [
+      "pop_count_test.cpp"
+    ],
+    "example": [
+      ".meta/example.cpp",
+      ".meta/example.h"
+    ]
+  },
+  "blurb": "Count the 1 bits in a number.",
+  "source": "Christian Willner, Eric Willigers",
+  "source_url": "https://forum.exercism.org/t/new-exercise-suggestion-pop-count/7632/5"
+}

exercises/practice/pop-count/.meta/example.cpp

@@ -0,0 +1,12 @@
+#include "pop_count.h"
+
+namespace chicken_coop {
+    int positions_to_quantity(int display_value) {
+        int counter{};
+        while (display_value != 0) {
+            if (display_value % 2) ++counter;
+            display_value /= 2;
+        }
+        return counter;
+    }
+}  // namespace chicken_coop

exercises/practice/pop-count/.meta/example.h

@@ -0,0 +1,5 @@
+#pragma once
+
+namespace chicken_coop {
+    int positions_to_quantity(int display_value);
+}  // namespace chicken_coop

exercises/practice/pop-count/.meta/tests.toml

@@ -0,0 +1,11 @@
+[559e789d-07d1-4422-9004-3b699f83bca3]
+description = "0 eggs"
+
+[97223282-f71e-490c-92f0-b3ec9e275aba]
+description = "1 egg"
+
+[1f8fd18f-26e9-4144-9a0e-57cdfc4f4ff5]
+description = "4 eggs"
+
+[0c18be92-a498-4ef2-bcbb-28ac4b06cb81]
+description = "13 eggs"

exercises/practice/pop-count/CMakeLists.txt

@@ -0,0 +1,64 @@
+# Get the exercise name from the current directory
+get_filename_component(exercise ${CMAKE_CURRENT_SOURCE_DIR} NAME)
+
+# Basic CMake project
+cmake_minimum_required(VERSION 3.5.1)
+
+# Name the project after the exercise
+project(${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 ${exercise_cpp} ${file}.h $<TARGET_OBJECTS:catchlib>)
+elseif(EXERCISM_TEST_SUITE)
+    # The Exercism test suite is being run, the Docker image already
+    # includes a pre-built version of Catch.
+    find_package(Catch2 REQUIRED)
+    add_executable(${exercise} ${file}_test.cpp ${exercise_cpp} ${file}.h)
+    target_link_libraries(${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 ${exercise_cpp} ${file}.h test/tests-main.cpp)
+endif()
+
+set_target_properties(${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})

exercises/practice/pop-count/pop_count.cpp

@@ -0,0 +1,7 @@
+#include "pop_count.h"
+
+namespace chicken_coop {
+
+
+
+}  // namespace chicken_coop

exercises/practice/pop-count/pop_count.h

@@ -0,0 +1,7 @@
+#pragma once
+
+namespace chicken_coop {
+
+
+
+}  // namespace chicken_coop

exercises/practice/pop-count/pop_count_test.cpp

@@ -0,0 +1,30 @@
+#include "pop_count.h"
+#ifdef EXERCISM_TEST_SUITE
+#include <catch2/catch.hpp>
+#else
+#include "test/catch.hpp"
+#endif
+
+TEST_CASE("0 eggs")
+{
+    REQUIRE(chicken_coop::positions_to_quantity(0) == 0);
+}
+
+#if defined(EXERCISM_RUN_ALL_TESTS)
+
+TEST_CASE("1 egg")
+{
+    REQUIRE(chicken_coop::positions_to_quantity(16) == 1);
+}
+
+TEST_CASE("4 eggs")
+{
+    REQUIRE(chicken_coop::positions_to_quantity(89) == 4);
+}
+
+TEST_CASE("13 eggs")
+{
+    REQUIRE(chicken_coop::positions_to_quantity(2000000000) == 13);
+}
+
+#endif