Compilare: user.cpp: In function ‘void read()’: user.cpp:16: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:25: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp: In function ‘void dfs1(int)’: user.cpp:33: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘void expand(int)’: user.cpp:44: 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 ‘int main()’: user.cpp:78: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:79: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result