Compilare: user.cpp: In function ‘int inorder_next(pitem)’: user.cpp:78:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=1;i<vt.size();i++){ ^ user.cpp: In function ‘int inorder_prev(pitem)’: user.cpp:93:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=1;i<vt.size();i++){ ^ user.cpp: In function ‘int inorder_next(pitem)’: user.cpp:83:1: warning: control reaches end of non-void function [-Wreturn-type] } ^ user.cpp: In function ‘int inorder_prev(pitem)’: user.cpp:97:1: warning: control reaches end of non-void function [-Wreturn-type] } ^