radix_sort.cpp

Algorithms/Sorting/radix_sort.cpp

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+// Radix Sort in C++ Programming
+
+#include <iostream>
+using namespace std;
+
+int getMax(int array[], int n) {
+  int max = array[0];
+  for (int i = 1; i < n; i++)
+    if (array[i] > max)
+      max = array[i];
+  return max;
+}
+
+void countingSort(int array[], int size, int place) {
+  const int max = 10;
+  int output[size];
+  int count[max];
+
+  for (int i = 0; i < max; ++i)
+    count[i] = 0;
+
+  for (int i = 0; i < size; i++)
+    count[(array[i] / place) % 10]++;
+
+  for (int i = 1; i < max; i++)
+    count[i] += count[i - 1];
+
+  for (int i = size - 1; i >= 0; i--) {
+    output[count[(array[i] / place) % 10] - 1] = array[i];
+    count[(array[i] / place) % 10]--;
+  }
+
+  for (int i = 0; i < size; i++)
+    array[i] = output[i];
+}
+
+void radixsort(int array[], int size) {
+
+  int max = getMax(array, size);
+  for (int place = 1; max / place > 0; place *= 10)
+    countingSort(array, size, place);
+}
+
+
+void printArray(int array[], int size) {
+  int i;
+  for (i = 0; i < size; i++)
+    cout << array[i] << " ";
+  cout << endl;
+}
+
+
+int main() {
+  int array[] = {121, 432, 564, 23, 1, 45, 788};
+  int n = sizeof(array) / sizeof(array[0]);
+  radixsort(array, n);
+  printArray(array, n);
+}