Compilare: user.cpp: In function ‘void FILL(int, int*, int)’: user.cpp:18:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0; j<a[i].size(); ++j){ //cout<<i<<" "<<a[i][j]<<"\n"; ~^~~~~~~~~~~~ user.cpp: In function ‘int main()’: user.cpp:45:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0; i<a[c].size() && b; ++i){ ~^~~~~~~~~~~~ user.cpp:27:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("graf.in","r",stdin); ^ user.cpp:28:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("graf.out","w",stdout); ^