Compilare: user.cpp: In function ‘int mark(int, int, int)’: user.cpp:16:1: warning: no return statement in function returning non-void [-Wreturn-type] } ^ user.cpp: In function ‘int back(int, int)’: user.cpp:50:1: warning: no return statement in function returning non-void [-Wreturn-type] } ^ user.cpp: In function ‘int main()’: user.cpp:56:6: warning: unused variable ‘i’ [-Wunused-variable] int i,x,y; ^