bile1.cpp: In function 'void dfsa(int)': bile1.cpp:13: warning: comparison between signed and unsigned integer expressions bile1.cpp: In function 'void dfsb(int)': bile1.cpp:21: warning: comparison between signed and unsigned integer expressions bile1.cpp: In function 'int main()': bile1.cpp:26: warning: unused variable 'pp' bile1.cpp:26: warning: unused variable 'j' bile1.cpp:27: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result bile1.cpp:28: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result bile1.cpp:29: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result bile1.cpp:31: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result