Compilare: user.cpp: In function ‘int main()’: user.cpp:24:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("largestroot.in","r",stdin); ^ user.cpp:25:42: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("largestroot.out","w",stdout); ^ user.cpp:27:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] for (scanf("%lld", &T); T ; --T) ^ user.cpp:29:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%lld\n", &n); ^ user.cpp:35:38: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] ok = false; gets(sir + 1); m = strlen(sir + 1); if (sir[1] == '-') ok = true; ^ /tmp/ccAqAYsA.o: In function `main': user.cpp:(.text.startup+0x101): warning: the `gets' function is dangerous and should not be used.