Compilare: user.c: In function 'main': user.c:20: warning: implicit declaration of function 'strlen' user.c:20: warning: incompatible implicit declaration of built-in function 'strlen' user.c:14: warning: unused variable 'it' user.c:14: warning: unused variable 'd' user.c:14: warning: unused variable 'num2' user.c:14: warning: unused variable 'num1' /tmp/ccgPgwIu.o: In function `main': user.c:(.text+0x3a): warning: the `gets' function is dangerous and should not be used.