Compilare: user.cpp: In function ‘void apm()’: user.cpp:32:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(k=0; k<v[b].size(); k++) ^ user.cpp: In function ‘int main()’: user.cpp:55:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0; i<v[1].size(); i++) ^ user.cpp:46:11: warning: unused variable ‘j’ [-Wunused-variable] int i,j,x,y,c; ^