Compilare: user.cpp: In function ‘int main()’: user.cpp:22:29: 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:23:31: 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:25:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &N, &K); ^ user.cpp:15:27: warning: ‘b’ may be used uninitialized in this function [-Wmaybe-uninitialized] if (a >= MOD) a -= MOD; ^ user.cpp:20:30: note: ‘b’ was declared here int i, j, k, t, p, q, a, b, c, A[2][2], B[2][2], now, next; ^ user.cpp:15:27: warning: ‘a’ may be used uninitialized in this function [-Wmaybe-uninitialized] if (a >= MOD) a -= MOD; ^ user.cpp:20:27: note: ‘a’ was declared here int i, j, k, t, p, q, a, b, c, A[2][2], B[2][2], now, next; ^