Compilare: user.cpp: In function ‘int main()’: user.cpp:7:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("trompeta.in","r",stdin); ^ user.cpp:8:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("trompeta.out","w",stdout); ^ user.cpp:9:25: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%c",&n,&m,&c); ^ user.cpp:11:8: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(s); ^ /tmp/cc3SEi0e.o: In function `main': user.cpp:(.text.startup+0x8a): warning: the `gets' function is dangerous and should not be used.