Compilare: user.cpp: In function ‘void dfs(int, int)’: user.cpp:36: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘void dfs1(int)’: user.cpp:48: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘void dfs2(int)’: user.cpp:60: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘void dfs3(int)’: user.cpp:76: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘int main()’: user.cpp:89: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:90: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:91: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:96: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result