Compilare: user.cpp: In function ‘int main()’: user.cpp:9:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("showroom.in","r",stdin); ^ 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("showroom.out","w",stdout); ^ user.cpp:11:36: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d%d\n",&n,&a,&r,&k); ^ user.cpp:12:12: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(v); ^ user.cpp:23:16: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(v); ^ /tmp/cch0xeBw.o: In function `main': user.cpp:(.text.startup+0x80): warning: the `gets' function is dangerous and should not be used.