Compilare: user.cpp:50:2: warning: no newline at end of file user.cpp: In function 'int eval(int, char, int)': user.cpp:22: warning: control reaches end of non-void function user.cpp: In function 'int eval(int)': user.cpp:25: warning: 'x' may be used uninitialized in this function user.cpp:25: warning: 'x' may be used uninitialized in this function user.cpp:25: warning: 'x' may be used uninitialized in this function