Compilare: user.cpp: In function ‘mult operator*(mult, mult)’: user.cpp:14:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<X.size();i++) ~^~~~~~~~~ user.cpp:16:13: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(j==Y.size()) break; ~^~~~~~~~~~ user.cpp: In function ‘mult operator+(mult, mult)’: user.cpp:27:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<X.size();i++) fr[X[i]]=1; ~^~~~~~~~~ user.cpp:28:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<Y.size();i++) fr[Y[i]]=1; ~^~~~~~~~~ user.cpp: In function ‘mult operator-(mult, mult)’: user.cpp:39:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<X.size();i++) ~^~~~~~~~~ user.cpp:41:13: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(j==P.size()) break; ~^~~~~~~~~~ user.cpp:45:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=P.size();i<X.size();i++) ~^~~~~~~~~