Compilare: user.cpp: In function ‘void dfs(int)’: user.cpp:55:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i=0;i<v[nod].size();i++) { ^ user.cpp: In function ‘void add(char)’: user.cpp:68:29: warning: null argument where non-null required (argument 2) [-Wnonnull] memcpy(s,0,sizeof(s)); ^ user.cpp: In function ‘int main()’: user.cpp:75:11: warning: unused variable ‘j’ [-Wunused-variable] int i,j,a,b; ^ user.cpp:74:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("maimute.out","w",stdout); ^ user.cpp: In constructor ‘instream::instream(const char*)’: user.cpp:20:44: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buffer,SIZE,1,input_file); ^ user.cpp: In member function ‘void instream::advance()’: user.cpp:42:48: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buffer,SIZE,1,input_file); ^