dragoni.cpp: In function 'int main()': dragoni.cpp:10: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result dragoni.cpp:11: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result dragoni.cpp: In function 'void DFS(int)': dragoni.cpp:37: warning: comparison between signed and unsigned integer expressions dragoni.cpp: In function 'void drum(int, int, int)': dragoni.cpp:56: warning: comparison between signed and unsigned integer expressions