Compilare: user.cpp: In function 'int op0(int)': user.cpp:17: warning: control reaches end of non-void function user.cpp: In function 'int op1(int)': user.cpp:22: warning: 'last' may be used uninitialized in this function user.cpp: In function 'int op2(int)': user.cpp:36: warning: 'last' may be used uninitialized in this function