c++ - 如何将未知大小的二维矩阵发送给函数

Question

我想弄清楚如何将二维矩阵传递给函数

//function to print Matrix
void refl(int n, int board[][])
{
    for(int i=0; i<n; i++)
    {
        for(int j=0; j<n; j++)
        {

            cout << board[i][j]  << "  ";
            }
        cout << endl; //printing the matrix to the screen
    }
}

int main()
{
    int n;
    string refl;
    cin>>n;
    int board[n][n]; //creates a n*n matrix or a 2d array.

        for(int i=0; i<n; i++)    //This loops on the rows.
    {
        for(int j=0; j<n; j++) //This loops on the columns
            cin>>board[i][j];
    refl(n , board);
    }

return 0;
}

它说“n”和“board”在函数中声明时未声明。

Answer 1

尝试使用 C++ std::vector 或优秀的旧 C malloc+free。

C++

#include <string>
#include <iostream>
#include <vector>

using namespace std;

void reflxx(int n, vector<vector<int>>& board)
{
    for(int i=0; i<n; i++)
    {
        for(int j=0; j<n; j++)
        {

            cout << board[i][j]  << "  ";
            }
        cout << endl; //printing the matrix to the screen
    }
}

int main()
{
    int n;
    string refl;
    cin>>n;
    vector<vector<int>> board(n, vector<int>(n));
     //creates a n*n matrix or a 2d array.

        for(int i=0; i<n; i++)    //This loops on the rows.
    {
        for(int j=0; j<n; j++) //This loops on the columns
            cin>>board[i][j];
    }
    reflxx(n , board);

return 0;
}

参见 http://www.cplusplus.com/reference/vector/vector/resize/更多示例。