Compilare: user.cpp: In function ‘void det()’: user.cpp:23:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<a[x].size();i++) ^ user.cpp:14:8: warning: unused variable ‘j’ [-Wunused-variable] int i,j,st=0,dr=0,x; ^ user.cpp:14:10: warning: unused variable ‘st’ [-Wunused-variable] int i,j,st=0,dr=0,x; ^ user.cpp:14:15: warning: unused variable ‘dr’ [-Wunused-variable] int i,j,st=0,dr=0,x; ^