Compilare: user.cpp: In constructor 'op::op()': user.cpp:6: warning: 'op::val' will be initialized after user.cpp:5: warning: 'bool op::isOp' user.cpp:7: warning: when initialized here user.cpp: In constructor 'op::op(char, bool)': user.cpp:6: warning: 'op::val' will be initialized after user.cpp:5: warning: 'bool op::isOp' user.cpp:8: warning: when initialized here user.cpp: In function 'int main()': user.cpp:92: warning: comparison between signed and unsigned integer expressions user.cpp:96: warning: comparison between signed and unsigned integer expressions