Compilare: user.cpp: In function ‘int main()’: user.cpp:71:37: 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:72:39: 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:74:43: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d %d\n", &n, &x, &r, &k); ^ user.cpp:78:18: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(s+1); int m = strlen(s+1); s[m+1] = ' '; ^ user.cpp:91:35: warning: ‘f’ may be used uninitialized in this function [-Wmaybe-uninitialized] else unite(f , ss); ^ /tmp/cc76yt9f.o: In function `main': user.cpp:(.text.startup+0xa0): warning: the `gets' function is dangerous and should not be used.