Compilare: user.c: In function 'main': user.c:44: warning: 'return' with no value, in function returning non-void user.c:103: warning: format '%i' expects type 'int', but argument 3 has type 'long unsigned int' user.c:27: warning: unused variable 'U2' user.c:62: warning: 'poz' may be used uninitialized in this function