Compilare: user.cpp: In function ‘bigint operator+(bigint, bigint)’: user.cpp:42:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=m;i<a.D.size();i++) ~^~~~~~~~~~~ user.cpp:47:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=m;i<b.D.size();i++) ~^~~~~~~~~~~ user.cpp: In function ‘bigint operator*(bigint, bigint)’: user.cpp:60:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<b.D.size();i++) ~^~~~~~~~~~~