Add example for insertion sort

cpp/algorithms/sorting/CMakeLists.txt

@@ -17,3 +17,4 @@ project (
 
 add_subdirectory(merge)
 add_subdirectory(selection)
+add_subdirectory(insertion)

cpp/algorithms/sorting/insertion/CMakeLists.txt

@@ -0,0 +1,17 @@
+###############################################################################
+## Author: Shaun Reed                                                        ##
+## Legal: All Content (c) 2021 Shaun Reed, all rights reserved               ##
+## About: A basic CMakeLists configuration to practice insertion sort        ##
+##                                                                           ##
+## Contact: shaunrd0@gmail.com  | URL: www.shaunreed.com | GitHub: shaunrd0  ##
+###############################################################################
+
+cmake_minimum_required(VERSION 3.16)
+project(InsertionSort LANGUAGES CXX)
+
+set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/bin)
+
+add_executable(insertion-sort "insertion-sort.cpp")
+
+add_library(lib-insertion "lib-insertion.cpp")
+target_link_libraries(insertion-sort lib-insertion)

cpp/algorithms/sorting/insertion/insertion-sort.cpp

@@ -0,0 +1,37 @@
+/*#############################################################################
+## Author: Shaun Reed                                                        ##
+## Legal: All Content (c) 2021 Shaun Reed, all rights reserved               ##
+## About: An example implementation of insertion sort using a custom library ##
+##                                                                           ##
+## Contact: shaunrd0@gmail.com  | URL: www.shaunreed.com | GitHub: shaunrd0  ##
+###############################################################################
+*/
+
+#include "lib-insertion.hpp"
+
+#include <algorithm>
+#include <vector>
+#include <random>
+#include <iostream>
+
+int main(const int argc, const char * argv[])
+{
+  srand(time(nullptr));
+  std::vector<int> array(ARRAY_LENGTH);
+  std::generate(array.begin(), array.end(), [](){ return rand() % 1000;});
+
+  auto print = [](std::vector<int> array) {
+    for (const auto &i : array) {
+      std::cout << i << ", ";
+    }
+    std::cout << std::endl;
+  };
+
+  std::cout << "Unsorted array: \n";
+  print(array);
+
+  InsertionSort(array);
+
+  std::cout << "Sorted array: \n";
+  print(array);
+}

cpp/algorithms/sorting/insertion/lib-insertion.cpp

@@ -0,0 +1,39 @@
+/*#############################################################################
+## Author: Shaun Reed                                                        ##
+## Legal: All Content (c) 2021 Shaun Reed, all rights reserved               ##
+## About: An example implementation of insertion sort using a custom library ##
+##                                                                           ##
+## Contact: shaunrd0@gmail.com  | URL: www.shaunreed.com | GitHub: shaunrd0  ##
+###############################################################################
+*/
+
+#include "lib-insertion.hpp"
+
+#include <algorithm>
+#include <vector>
+
+void InsertionSort(std::vector<int> &array)
+{
+  // For each value, move left until we find sortedPosition for keyValue
+  // + Starting with keyValue at array[1], to check sortedPosition at array[0]
+  for (int keyIndex = 1; keyIndex <= array.size(); keyIndex++) {
+    // Save the current key value
+    // + We will look for the sorted position of this value
+    const int keyValue = array[keyIndex];
+    // First, check if the value at the previous index is > keyValue
+    int sortedPosition = keyIndex - 1;
+    // While array[sortedPosition] > keyValue
+    while (sortedPosition >= 0 && array[sortedPosition] > keyValue) {
+      // The value in the lower index is larger than the keyValue
+      // + Move the value at sortedPosition to the right (ascending order)
+      array[sortedPosition + 1] = array[sortedPosition];
+      // Decrement sortedPosition so we can check the next value
+      sortedPosition--;
+    }
+    // Insert the keyValue in its final sorted position
+    // + Once array[sortedPosition] < keyValue, keyValue belongs one index right
+    array[sortedPosition + 1] = keyValue;
+
+  }
+}
+

cpp/algorithms/sorting/insertion/lib-insertion.hpp

@@ -0,0 +1,19 @@
+/*#############################################################################
+## Author: Shaun Reed                                                        ##
+## Legal: All Content (c) 2021 Shaun Reed, all rights reserved               ##
+## About: An example implementation of insertion sort using a custom library ##
+##                                                                           ##
+## Contact: shaunrd0@gmail.com  | URL: www.shaunreed.com | GitHub: shaunrd0  ##
+###############################################################################
+*/
+
+#ifndef LIB_INSERTION_HPP
+#define LIB_INSERTION_HPP
+
+#include <vector>
+
+#define ARRAY_LENGTH 10
+
+void InsertionSort(std::vector<int> &array);
+
+#endif // LIB_INSERTION_HPP