Compilare: main.cpp: In function 'int main()': main.cpp:22:33: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("char.in","r",stdin); ^ main.cpp:23:35: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("char.out","w",stdout); ^ main.cpp:55:11: warning: 'maxi' may be used uninitialized in this function [-Wmaybe-uninitialized] cout<<maxi<<endl; ^~~~