TemplateMethod与快速排序

设计模式TemplateMethod模式，快速排序中2种不同的分割算法

#include <iostream>#include <algorithm>#include <time.h>#include <cassert>using namespace std;template <typename T>class AbstractQuickSort{public: void sort(T arr[], int begin, int end) { if (begin < end) { int middle = partition(arr, begin, end); sort(arr, begin, middle - 1); sort(arr, middle + 1, end); } }private: virtual int partition(T arr[], int begin, int end) = 0;};template <typename T>class QuickSortA: public AbstractQuickSort<T>{public:private: /* *Loop Invariant: *a. if i>= index >=begin, then arr[index] <= pivot *b. if j > index > i, then arr[index] > pivot *c. if end >= index >= j, then arr[index] to be tested. */ virtual int partition(T arr[], int begin, int end) { T pivot = arr[begin]; // Initialization int i = begin; int j = i + 1; // Maintenance while (j <= end) { if (arr[j] <= pivot) { i++; swap(arr[i], arr[j]); } j++; } // Termination swap(arr[begin], arr[i]); return i; }};template <typename T>class QuickSortB: public AbstractQuickSort<T>{public:private: /* *Loop Invariant: *a. if i> index >=begin, then arr[index] <= pivot *b. if j >= index >= i, then arr[index] to be tested *c. if end >= index > j, then arr[index] > pivot */ virtual int partition(T arr[], int begin, int end) { T pivot = arr[begin]; // Initialization int i = begin; int j = end; // Maintenance while (i < j) { while (i <= end && arr[i] <= pivot) i++; while (j >= begin && arr[j] > pivot) j--; if (i <= end && j >= begin && i < j) { swap(arr[i], arr[j]); } } // Termination swap(arr[begin], arr[i - 1]); return i - 1; }};template <typename T>void printArray(T arr[], int len){ for (int i = 0; i < len; i++) { cout << arr[i] << '/t'; } cout << endl;}template <typename T>void verifyIsSorted(T arr[], int len){ for (int i = 1; i < len; i++) { assert(arr[i] >= arr[i - 1]); }}const int len = 100;int arr[len];int ascendingArr[len];int descendingArr[len];int main(){ srand(time(0)); for (int i = 0; i < len; i++) { arr[i] = rand(); ascendingArr[i] = rand(); descendingArr[i] = rand(); } sort(ascendingArr, ascendingArr + len, less<int>()); sort(descendingArr, descendingArr + len, greater<int>()); AbstractQuickSort<int> *qs = new QuickSortB<int>(); qs->sort(ascendingArr, 0, len - 1); verifyIsSorted(ascendingArr, len); qs->sort(descendingArr, 0, len - 1); verifyIsSorted(descendingArr, len); qs->sort(arr, 0, len - 1); verifyIsSorted(arr, len); delete qs; system("pause"); return 0;}