lightbot.cpp: In function 'int main()': lightbot.cpp:9: warning: unused variable 'k' lightbot.cpp:9: warning: unused variable 'c' lightbot.cpp:9: warning: unused variable 'j' lightbot.cpp:9: warning: unused variable 'elem' lightbot.cpp:7: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result lightbot.cpp:8: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result lightbot.cpp:9: warning: 'ci' may be used uninitialized in this function