Compilare: user.cpp: In function ‘int main()’: user.cpp:45:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("enigma.in","r",stdin); ^ user.cpp:47:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&n,&m);gets(s); ^ user.cpp:47:32: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&n,&m);gets(s); ^ user.cpp:48:12: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(s); ^ user.cpp:51:16: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(a); ^ /tmp/ccHIPN3r.o: In function `main': user.cpp:(.text.startup+0x82): warning: the `gets' function is dangerous and should not be used.