C++将数组的元素顺序随机打乱

参考：

https://blog.csdn.net/cordova/article/details/52884399

https://zhidao.baidu.com/question/1604258083773493627.html

自己的测试代码

    int array1[] = {,,,,,,,,};

    int array2[] = {  };

    for (int i=;i>;i--)

    {

        int pos = rand() % i;

        printf("%d ", pos);

        array2[i] = array1[pos];

        for (int j = pos;j<;j++)

        {

            array1[j] = array1[j+];

        }

    }

    array2[] = array1[];

    printf("\n");

    for (int i = ; i<  ; i++)

    {

        printf("%d ", array2[i]);

    }

打乱之后，恢复：

#include<iostream>

using namespace std;

int main()

{

    char str[]="abcdefg123456789";

    char key[]="";

    char temp;

    /*利用秘钥乱序*/

    for(int j = ; j < ; j++)   //对于key的前两位

        for(int i = ;(i+(key[j]-''))<=; i++)

        {

                if(i%!=)//奇数位与其后面第key[j]位交换

                {

                temp = str[i+(key[j]-'')];

                str[i+(key[j]-'')] = str[i];

                str[i] = temp;

                }

        }

    for(int i = ; i < ; i++)

        cout<<str[i]<<" ";

    cout<<endl;

    for(int j = ; j < ; j++)    //对于key的后两位

        for(int i = ;(i+(key[j]-''))<=; i++)

        {

            if(i%==)//偶数位与其后面第key[j]位交换

            {

                temp = str[i+(key[j]-'')];

                str[i+(key[j]-'')] = str[i];

                str[i] = temp;

                }

        }

    for(int i = ; i < ; i++)

        cout<<str[i]<<" ";

    cout<<endl;

    /*利用秘钥复原*/

    for(int j = ; j >= ; j--)    //对于key的后两位

        for(int i = ;(i-(key[j]-''))>=; i--)

        {

            if(i%!=)//奇数位与其前面第key[j]位交换

            {

                temp = str[i-(key[j]-'')];

                str[i-(key[j]-'')] = str[i];

                str[i] = temp;

                }

        }

    for(int i = ; i < ; i++)

        cout<<str[i]<<" ";

    cout<<endl;

    for(int j = ; j >= ; j--)   //对于key的前两位

        for(int i = ;(i-(key[j]-''))>=; i--)

        {

                if(i%!=)//奇数位与其前面第key[j]位交换

                {

                temp = str[i-(key[j]-'')];

                str[i-(key[j]-'')] = str[i];

                str[i] = temp;

                }

        }

    for(int i = ; i < ; i++)

        cout<<str[i]<<" ";

    system("pause");

    return ;

}