Compilare: main.cpp: In function 'int main()': main.cpp:55:33: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("tris.in","r",stdin); ^ main.cpp:56:35: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("tris.out","w",stdout); ^ main.cpp:58:34: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d%d",&a,&b,&c,&d); ^