immortal.cpp: In function 'void back(int)': immortal.cpp:28: warning: suggest explicit braces to avoid ambiguous 'else' immortal.cpp: In function 'int main()': immortal.cpp:71: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result immortal.cpp:72: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result immortal.cpp:73: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result immortal.cpp:77: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result