Compilare: user.cpp: In function ‘int prefix()’: user.cpp:19: warning: no return statement in function returning non-void user.cpp: In function ‘int kmpp()’: user.cpp:35: warning: no return statement in function returning non-void user.cpp: In function ‘int main()’: user.cpp:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:40: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result user.cpp:41: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result /tmp/cc1KlQaI.o: In function `main': user.cpp:(.text+0x1a3): warning: the `gets' function is dangerous and should not be used.