cuburi.cpp: In function 'int second(int)': cuburi.cpp:24: warning: unused variable 'y' cuburi.cpp: In function 'int main()': cuburi.cpp:140: warning: unused variable 'k' cuburi.cpp:138: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result cuburi.cpp:139: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result cuburi.cpp:141: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result cuburi.cpp: In function 'int opposite(int)': cuburi.cpp:40: warning: control reaches end of non-void function