regat.cpp: In function 'void euler(int)': regat.cpp:37: warning: comparison between signed and unsigned integer expressions regat.cpp: In function 'void DFS(int)': regat.cpp:58: warning: comparison between signed and unsigned integer expressions regat.cpp: In function 'int main()': regat.cpp:76: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result regat.cpp:76: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result regat.cpp:77: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result regat.cpp:82: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result regat.cpp:89: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result