Compilare: user.cpp: In function ‘void read()’: user.cpp:28: warning: unused variable ‘semn’ user.cpp:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:31: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:36: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp: In function ‘void dfs(int)’: user.cpp:48: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘void prepare()’: user.cpp:62: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘void dfs2(int)’: user.cpp:78: warning: comparison between signed and unsigned integer expressions user.cpp:88: warning: comparison between signed and unsigned integer expressions user.cpp:97: warning: comparison between signed and unsigned integer expressions user.cpp:106: warning: comparison between signed and unsigned integer expressions user.cpp:109: warning: comparison between signed and unsigned integer expressions user.cpp:115: warning: comparison between signed and unsigned integer expressions user.cpp:125: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘int main()’: user.cpp:137: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:138: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result