Compilare: user.cpp: In function ‘void eval()’: user.cpp:120: warning: operation on ‘st1’ may be undefined user.cpp:120: warning: operation on ‘st1’ may be undefined user.cpp:121: warning: operation on ‘st1’ may be undefined user.cpp:121: warning: operation on ‘st1’ may be undefined user.cpp:122: warning: operation on ‘st1’ may be undefined user.cpp:122: warning: operation on ‘st1’ may be undefined user.cpp:123: warning: operation on ‘st1’ may be undefined user.cpp:123: warning: operation on ‘st1’ may be undefined user.cpp: In function ‘int conv(char)’: user.cpp:101: warning: control reaches end of non-void function