#include <iostream>
#include <iomanip>

using namespace std;

int m[5][5] =
{
    { 1,2,3,4,5},
    { 6,7,8,9,10},
    { 11,12,13,14,15},
    { 16,17,18,19,20},
    { 21,22,23,24,25}
};

int main([[maybe_unused]] int argc,
         [[maybe_unused]] const char * argv[])
{
    typedef int reduced_matrix[4][5];
    reduced_matrix& r = *(reduced_matrix*)(m+1);

    for(int i = 0; i < 4; ++i)
    {
        for(int j = 0; j < 5; ++j)
        {
            cout << r[i][j] << " ";
        }
        cout << endl;
    }

}