Compilare: user.cpp: In function ‘int main()’: user.cpp:21:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("4x4puzzle.in","r",stdin); ^ user.cpp:22:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("4x4puzzle.out","w",stdout); ^ user.cpp:24:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &q); ^ user.cpp:26:53: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] for (i = 1; i <= 16; i++) scanf("%d", &v[i]); ^