Compilare: user.cpp: In function ‘int main()’: user.cpp:56:51: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("infinitepatternmatching.in", "r", stdin); ^ user.cpp:57:53: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("infinitepatternmatching.out", "w", stdout); ^ user.cpp:59:37: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets (sir + 1), L = strlen (sir + 1); ^ /tmp/cc58RnYB.o: In function `main': user.cpp:(.text.startup+0x56): warning: the `gets' function is dangerous and should not be used.