Compilare: user.cpp: In function ‘void df(int)’: user.cpp:17:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (j=0;j<l[i].size();j++) ^ user.cpp: In function ‘void df2(int)’: user.cpp:35:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (j=0;j<l[i].size();j++) { ^ user.cpp:32:17: warning: unused variable ‘ok1’ [-Wunused-variable] int j,x,y,w,ok1,ok2; ^ user.cpp:32:21: warning: unused variable ‘ok2’ [-Wunused-variable] int j,x,y,w,ok1,ok2; ^ user.cpp: In function ‘int main()’: user.cpp:70:11: warning: unused variable ‘j’ [-Wunused-variable] int i,j,x,y; ^