Compilare: user.cpp: In function ‘void rc(int)’: user.cpp:59:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<gr[fr].size(); ++i) if(pre[gr[fr][i].x]==fr) { ^ user.cpp: In function ‘unsigned int getInt()’: user.cpp:81:40: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buf,maxb,1,fin),ptr=0; ^ user.cpp:85:40: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buf,maxb,1,fin),ptr=0; ^