Compilare: user.cpp: In function ‘void eval()’: user.cpp:108: warning: operation on ‘st1’ may be undefined user.cpp:108: warning: operation on ‘st1’ may be undefined user.cpp:109: warning: operation on ‘st1’ may be undefined user.cpp:109: warning: operation on ‘st1’ may be undefined user.cpp:110: warning: operation on ‘st1’ may be undefined user.cpp:110: warning: operation on ‘st1’ may be undefined user.cpp:111: warning: operation on ‘st1’ may be undefined user.cpp:111: warning: operation on ‘st1’ may be undefined user.cpp: In function ‘int conv(char)’: user.cpp:89: warning: control reaches end of non-void function