Compilare: user.cpp: In function ‘int main()’: user.cpp:66:29: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen(FIN, "r", stdin); ^ user.cpp:67:31: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen(FOUT, "w", stdout); ^ user.cpp:69:14: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(str); ^ user.cpp:70:21: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d ", &n); ^ user.cpp:74:19: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(word); ^ /tmp/ccfJQVAP.o: In function `main': user.cpp:(.text.startup+0x54): warning: the `gets' function is dangerous and should not be used.