Add example for radix sort

cpp/algorithms/sorting/radix/lib-radix.cpp

@@ -0,0 +1,29 @@
+
+#include "lib-radix.hpp"
+#include "lib-counting.hpp"
+
+#include <algorithm>
+#include <vector>
+
+
+void RadixSort(std::vector<int> &array)
+{
+  int maxValue = *std::max_element(array.begin(), array.end());
+  // Get the total number of digits in the maximum value within the set
+  // + 100 has 3 digits; 10 has 2 digits; etc..
+  int digits = 0;
+  for (int tempMax = maxValue; tempMax > 0; tempMax /= 10) digits++;
+
+  // For each placeValue of the maximum value within the set
+  for (int placeValue = 1; maxValue / placeValue > 0; placeValue *= 10) {
+    // Perform counting sort on all values, only considering the placeValue digit
+    // Result of sorting the first placeValue:
+    // + 12, 10, 15, 5, 3, 101, 109, 115 -> 10, 101, 12, 3, 115, 15, 5, 109
+    // Result of sorting the second placeValue:
+    // + 10, 101, 12, 3, 115, 15, 5, 109 -> 3, 5, 101, 109, 10, 12, 115, 15
+    // Result of sorting the third placeValue:
+    // + 3, 5, 101, 109, 10, 12, 115, 15 -> 3, 5, 10, 12, 15, 101, 109, 115
+    CountingSort(array, placeValue);
+  }
+
+}