Compilare: user.cpp: In function ‘void read()’: user.cpp:21:24: warning: format ‘%s’ expects argument of type ‘char*’, but argument 2 has type ‘char (*)[13]’ [-Wformat=] scanf("%s", &ln); ^ user.cpp:23:29: warning: NULL used in arithmetic [-Wpointer-arith] for(i = 0; ln[i] != NULL; ++ i) ^~~~ user.cpp:16:17: warning: unused variable ‘x’ [-Wunused-variable] int cnt, i, x; ^ user.cpp:18:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d\n", &n, &d); ^ user.cpp:21:25: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%s", &ln); ^ user.cpp: In function ‘int main()’: user.cpp:40:44: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("slidingwindow.in", "r", stdin); ^ user.cpp:41:46: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("slidingwindow.out", "w", stdout); ^