Transpusa unei matrici c++

#include <iostream>
#include <time.h>
#include <stdio.h>

using namespace std;
#define nr_lin 3
#define nr_col 2

int main() {
    srand(time(0));
    int i, j,nr_inc=1, mat[nr_lin][nr_col], mat2[nr_col][nr_lin];

    for (i = 0; i < nr_lin; i++) {
        for (j = 0; j < nr_col;j++) {
            mat[i][j] = nr_inc++;
        }
    }

    cout << endl;

    for (i = 0; i < nr_lin; i++) {
        for (j = 0; j < nr_col; j++) {
            cout << mat[i][j] << " ";
        }
        cout << endl;
    }

    cout << endl;

    for (j = 0; j < nr_col;j++) {
        for (i = 0; i < nr_lin;i++) {
            mat2[j][i] = mat[i][j];
        }

    }

    for (i = 0; i < nr_col; i++) {
        for (j = 0; j < nr_lin; j++) {
            cout << mat2[i][j] << " ";
        }
        cout << endl;
    }


    system("pause");
}