Compilare: user.cpp: In function ‘int main()’: user.cpp:20:15: warning: iteration 3 invokes undefined behavior [-Waggressive-loop-optimizations] if (v[1][i] == '0') ~~~~~~^ user.cpp:19:21: note: within this loop for (int i = 1; i <= 4; i++) ~~^~~~ user.cpp:17:21: warning: array subscript is above array bounds [-Warray-bounds] v[i][1] = v[i][4] = '0'; ~~~~~~^