Compilare: user.c: In function ‘introducere_chei’: user.c:75:9: warning: implicit declaration of function ‘isalpha’ [-Wimplicit-function-declaration] if(isalpha(token[0]) != 0 || isdigit(token[0]) != 0) ^ user.c:75:9: warning: implicit declaration of function ‘isdigit’ [-Wimplicit-function-declaration] user.c: In function ‘main’: user.c:113:9: warning: unused variable ‘nr_carac’ [-Wunused-variable] int nr_carac, nr_chei; ^