思路：
递归思想。我们有n张牌，不妨先假设有一个洗牌函数shuffle(....)，能完美的洗出n-1张牌 。拿第n张牌来打乱前面n-1的洗牌顺序，从而得到n张牌的最终结果。
代码如下：
1 #include <iostream> 2 #include <cstdlib> 3 using namespace std; 4 5 //随机指定区域内的数 6 int MyRand(int low, int high) 7 { 8 return low + rand() % (high - low + 1); 9 } 10 11 int* shuffle(int* cards, int n) 12 { 13 if (n <= 0) 14 return cards; 15 16 shuffle(cards, n - 1); 17 int rand = MyRand(0, n); 18 19 int temp = cards[rand]; 20 cards[rand] = cards[n]; 21 cards[n] = temp; 22 23 return cards; 24 } 25 26 int main() 27 { 28 for (int k = 1; k <= 10; k++) 29 { 30 int cards[52] = { 31 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 32 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 33 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 34 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 35 47, 48, 49, 50, 51, 52, 36 }; 37 cout << endl; 38 shuffle(cards, 52);// 洗牌 39 for (int i = 1; i <= 52; i++) 40 { 41 cout << cards[i - 1] << " "; 42 if (i % 13 == 0) 43 cout << endl; 44 } 45 } 46 cout << endl; 47 system("PAUSE"); 48 return 0; 49 }
输出结果：
1 4 18 17 14 36 6 41 20 26 29 1 39 12 2 51 48 49 13 27 10 34 31 47 8 52 45 35 3 40 4 38 25 3 24 19 22 21 44 32 30 15 4 50 16 2 33 11 5 7 23 46 42 37 43 9 5 6 11 36 41 28 48 35 29 30 10 15 40 44 31 7 26 33 8 7 12 32 23 14 46 45 6 21 24 8 3 25 1 13 18 20 39 52 5 4 47 17 42 9 50 16 2 37 38 9 19 43 27 34 28 22 51 10 11 2 17 33 13 19 32 44 8 12 23 52 51 45 12 4 26 1 14 38 3 43 21 39 11 9 42 46 13 35 34 31 47 29 41 18 25 40 48 6 10 30 14 36 15 24 49 37 5 27 28 50 49 16 20 22 15 16 31 12 5 39 35 47 9 23 16 41 20 24 48 17 21 11 30 13 7 43 38 49 40 46 19 50 52 18 44 14 6 45 18 1 17 32 4 28 27 8 2 19 36 33 15 42 34 29 25 37 10 26 51 22 7 20 21 47 23 11 36 18 40 25 32 39 7 42 4 22 22 48 49 33 3 30 43 41 12 6 15 24 37 28 23 27 50 51 19 16 29 3 5 2 26 10 35 52 24 1 38 45 34 21 13 31 17 14 46 9 8 44 25 26 ........
从结果来看上去很完美，剩下就是要在随机函数上做文章了，如果有一个完美的随机数发生器，那么这就是一个完美的洗牌算法。
通常递归的方法都能最换成迭代法，代码如下：
1 void shuffle2(int* cards, int n) 2 { 3 // 随机i-1中的任意一个数与i交换 4 for (int i = 0; i < n; i++) 5 { 6 int rand = MyRand(0, i); 7 int temp = cards[rand]; 8 cards[rand] = cards[i]; 9 cards[i] = temp; 10 } 11 }
Done！还不赖~~~