Compilare: user.cpp: In function ‘void eval()’: user.cpp:107: warning: operation on ‘st1’ may be undefined user.cpp:107: warning: operation on ‘st1’ may be undefined 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: In function ‘int conv(char)’: user.cpp:88: warning: control reaches end of non-void function