Compilare: user.cpp: In function ‘void eval()’: 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:112: warning: operation on ‘st1’ may be undefined user.cpp:112: warning: operation on ‘st1’ may be undefined user.cpp:113: warning: operation on ‘st1’ may be undefined user.cpp:113: warning: operation on ‘st1’ may be undefined user.cpp: In function ‘int conv(char)’: user.cpp:91: warning: control reaches end of non-void function