编译没有错误但是没有输出，怎会如此

代码如图，题目在最后11111111111111111111111111111111111111111111111111111111111111

#include <iostream>
#include <cstring>
using namespace std;

class CMatrix
{
public:
    CMatrix(int m, int n)
        :M(m),N(n)
    {
        p = new int[m*n];
        memset(p, 0, m*n * sizeof(int));
    }

    CMatrix(const CMatrix &other)
    {
        this->M = other.M;

        this->N = other.N;

        this->p = new int[M*N];
        memset(p, 0, M*N * sizeof(int));
        memcpy(p, other.p,M*N*sizeof(int));
    }

    ~CMatrix()
    {
        delete p;
    }

    int& ElementAt(int i, int j)
    {
        return p[i*N + j];
    }

    CMatrix Rotate()
    {
        CMatrix m(N,M);

        for (int i = 0; i < N; i++)
        {
            for (int j = 0; j < M; j++)
            {
                m.ElementAt(i, j) = ElementAt(j,i);
            }
        }

        return m;
    }
    void Display()
    {
        for (int i = 0; i < M; i++)
        {
            for (int j = 0; j < N; j++)
            {
                cout << p[i*N + j] <<" ";
            }
            cout << endl;
        }
    }
private:
    int M;
    int N;
    int* p;
};


int main() 
{
    int m = 3, n = 4;
    CMatrix A(m,n);
    for (int i=0;i<m;i++)
    {
        for (int j=0;j<n;j++)
        {
            A.ElementAt(i, j) = i * n + j + 1;
        }
    }
    A.Display();
    CMatrix B = A.Rotate();
    B.Display();
    return 0;
}