Compilare: user.c: In function ‘main’: user.c:18:5: warning: implicit declaration of function ‘malloc’ [-Wimplicit-function-declaration] char* str = malloc(34 * sizeof(char)); ^ user.c:18:17: warning: incompatible implicit declaration of built-in function ‘malloc’ [enabled by default] char* str = malloc(34 * sizeof(char)); ^ user.c:31:9: warning: format ‘%d’ expects argument of type ‘int’, but argument 3 has type ‘long long int’ [-Wformat=] fprintf(out, "%d\n", A); ^