Compilare: user.cpp: In function ‘int main()’: user.cpp:34:20: warning: converting to non-pointer type ‘char’ from NULL [-Wconversion-null] sir[i + 2] = NULL; ^ user.cpp:10:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("interzis.in", "r", stdin); ^ user.cpp:11:41: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("interzis.out", "w", stdout); ^ user.cpp:15:39: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d\n%s", &n, &l, str + 1); ^