3.

3.#

 1#include <iostream>
 2
 3using namespace std;
 4
 5void fun(int* arr, int n) {
 6  for (int i = 0; i < n; i++) {
 7    for (int j = 0; j < n; j++) {
 8      *(arr + n * i + j) = *(arr + n * j + i)
 9          = *(arr + n * i + j) * *(arr + n * j + i);
10    }
11  }
12}
13
14int main() {
15  int Arr[4][4] = {};
16  int count     = 0;
17  for (int i = 0; i < 4; i++) {
18    for (int j = 0; j < 4; j++) {
19      Arr[i][j] = count++;
20    }
21  }
22
23  fun(&Arr[0][0], 4);
24
25  for (int i = 0; i < 4; i++) {
26    for (int j = 0; j < 4; j++) {
27      cout << Arr[i][j] << "\t";
28    }
29    cout << endl;
30  }
31}