Compilare: user.cpp: In function ‘void read()’: user.cpp:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:23: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp: In function ‘void dfs(int)’: user.cpp:39: warning: comparison between signed and unsigned integer expressions user.cpp:49: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘int main()’: user.cpp:104: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:105: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:106: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result