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:17: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp: In function ‘void dfs(int)’: user.cpp:26: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘int ok(int)’: user.cpp:49: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘int main()’: user.cpp:95: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:96: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result