Compilare: main.cpp: In function 'int main()': main.cpp:431:8: warning: unused variable 'k' [-Wunused-variable] bool k = ok(a); ^ main.cpp:421:37: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen ("pastila.in", "r", stdin); ^ main.cpp:422:39: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen ("pastila.out", "w", stdout); ^