Compilare: user.cpp: In function ‘void read()’: user.cpp:13: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:16: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:19: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp: In function ‘void dfs(int)’: user.cpp:31: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘void dfs2(int)’: user.cpp:49: warning: comparison between signed and unsigned integer expressions user.cpp:68: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘void dfs3(int)’: user.cpp:79: warning: comparison between signed and unsigned integer expressions user.cpp:98: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘void dfs4(int)’: user.cpp:109: warning: comparison between signed and unsigned integer expressions user.cpp:128: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘int main()’: user.cpp:138: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:139: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result