Compilare: user.cpp: In function ‘int main()’: user.cpp:16:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("bool.in","r",stdin); ^ user.cpp:17:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("bool.out","w",stdout); ^ user.cpp:21:16: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(P); ^ user.cpp:24:31: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] for (scanf("%d\n", &N); N; N--) ^ user.cpp:26:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%c", &x); ^ /tmp/ccG1onso.o: In function `main': user.cpp:(.text.startup+0x59): warning: the `gets' function is dangerous and should not be used.