Compilare: user.cpp: In function ‘int main()’: user.cpp:21:29: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen(FIN, "r", stdin); ^ user.cpp:22:31: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen(FOUT, "w", stdout); ^ user.cpp:24:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &N, &K); ^ user.cpp:13:11: warning: ‘b’ may be used uninitialized in this function [-Wmaybe-uninitialized] a += b; ^ user.cpp:19:30: note: ‘b’ was declared here int i, j, k, t, p, q, a, b, c, A[2][2], B[2][2]; ^ user.cpp:13:11: warning: ‘a’ may be used uninitialized in this function [-Wmaybe-uninitialized] a += b; ^ user.cpp:19:27: note: ‘a’ was declared here int i, j, k, t, p, q, a, b, c, A[2][2], B[2][2]; ^