ghinion.cpp: In function 'void adun(long long int)': ghinion.cpp:22: warning: operation on 'c1' may be undefined ghinion.cpp: In function 'void backt()': ghinion.cpp:76: warning: unused variable 'es' ghinion.cpp:76: warning: unused variable 'ev' ghinion.cpp: In function 'int main()': ghinion.cpp:130: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result ghinion.cpp:131: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result ghinion.cpp:132: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result