Compilare: user.c: In function 'scan': user.c:11: warning: implicit declaration of function 'strlen' user.c:11: warning: incompatible implicit declaration of built-in function 'strlen' user.c: In function 'solve': user.c:20: warning: unused variable 'j' user.c: In function 'main': user.c:39: warning: control reaches end of non-void function /tmp/ccyCbzU2.o: In function `scan': user.c:(.text+0x1a8): warning: the `gets' function is dangerous and should not be used.