Compilare: user.cpp: In function ‘int main()’: user.cpp:8:8: warning: variable ‘fi’ set but not used [-Wunused-but-set-variable] FILE *fi, *fo; ^ user.cpp:8:13: warning: variable ‘fo’ set but not used [-Wunused-but-set-variable] FILE *fi, *fo; ^ user.cpp:12:10: warning: unused variable ‘f’ [-Wunused-variable] char c, f; ^ user.cpp:19:23: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &n, &k); ^ user.cpp:21:18: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%s", str); ^