Compilare: user.c: In function 'main': user.c:39: warning: unused variable 'i' user.c: In function 'convert': user.c:83: warning: unused variable 'p' user.c: In function 'eval': user.c:139: warning: unused variable 'aux' user.c: In function 'top': user.c:255: warning: control reaches end of non-void function user.c: In function 'prior': user.c:222: warning: control reaches end of non-void function