Compilare: user.c: In function ‘main’: user.c:19: warning: implicit declaration of function ‘strtok’ user.c:19: warning: assignment makes pointer from integer without a cast user.c:23: warning: implicit declaration of function ‘strlen’ user.c:23: warning: incompatible implicit declaration of built-in function ‘strlen’ user.c:24: warning: assignment makes pointer from integer without a cast