Compilare: user.cpp: In function ‘int s_1(int)’: user.cpp:13:1: warning: no return statement in function returning non-void [-Wreturn-type] } ^ user.cpp: In function ‘int s_4(int)’: user.cpp:18:1: warning: no return statement in function returning non-void [-Wreturn-type] } ^ user.cpp: In function ‘int s_3(int)’: user.cpp:24:1: warning: no return statement in function returning non-void [-Wreturn-type] } ^ user.cpp: In function ‘int s_2(int)’: user.cpp:30:1: warning: no return statement in function returning non-void [-Wreturn-type] } ^