Compilare: user.cpp: In function ‘int** read_matrix(int)’: user.cpp:25:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &m[i][j]); ^ user.cpp: In function ‘int main(int, char**)’: user.cpp:88:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("cartele.in", "r", stdin); ^ user.cpp:89:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("cartele.out", "w", stdout); ^ user.cpp:92:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &N, &C); ^