以下是一个生成数独的程序，利用深度优先遍历的方式。每次生成的数独是随机的。

对于判断一个点是否正确摆放的函数IsRightPlace()，要注意几个关键点。

//mySIZE是数独棋盘的边长，棋盘是mySIZE*mySIZE的大小  int mySIZE = 9;    void print(const vector<vector<int>> &num)  {   for (int i = 0; i < mySIZE; i++)   {    for (int j = 0; j < mySIZE; j++)    {     cout << num[i][j] << " ";    }    cout << endl;   }  }    bool IsRightPlace(vector<vector<int>> &num, int row, int col)  {   int n = num[row][col];   //注意i < row   for (int i = 0; i < row; i++)   {    if (num[i][col] == n)     return false;   }   //注意i < col   for (int i = 0; i < col; i++)   {    if (num[row][i] == n)     return false;   }   int row_start = row / 3;   row_start *= 3;   int row_end = row_start + 2;   int col_start = col / 3;   col_start *= 3;   int col_end = col_start + 2;   int i = row_start, j = col_start;   //注意 k <= 8   for (int k = 1; k <= 8; k++)   {    if (row != i || col != j)    {     if (num[i][j] == n)      return false;    }    else     break;    if (j == col_end)    {     //注意j = col_start ！不要搞错换行时列的起始点！     j = col_start;     i = i + 1;    }    else    {     j = j + 1;    }   }   return true;  }    bool generate_core(vector<vector<int>> &num, int row, int col)  {      vector<int> number;   for (int i = 1; i <= 9; i++)    number.emplace_back(i);   while (!number.empty())   {    int randindex = rand() % number.size();    int randnum = number[randindex];    number.erase(number.begin() + randindex);    num[row][col] = randnum;    if (IsRightPlace(num, row, col) == false)     continue;    if (row == mySIZE - 1 && col == mySIZE-1)    {     return true;    }    int nextrow, nextcol;    if (col == mySIZE-1)    {     nextrow=row + 1;     nextcol = 0;    }    else    {     nextrow = row;     nextcol = col + 1;    }    bool next = generate_core(num, nextrow, nextcol);    if (next)     return true;   }   if (number.empty())   {    num[row][col] = -5;    return false;   }    }    void generate()  {   vector<vector<int>> num(mySIZE, vector<int>(mySIZE, -1));   srand((unsigned)time(NULL));   if( generate_core(num, 0, 0) )    print(num);  }