autostrazi.cpp: In function 'void read()': autostrazi.cpp:20: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result autostrazi.cpp:22: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result autostrazi.cpp: In function 'void dfs(int)': autostrazi.cpp:30: warning: comparison between signed and unsigned integer expressions autostrazi.cpp:41: warning: name lookup of 'x' changed autostrazi.cpp:25: warning: matches this 'x' under ISO standard rules autostrazi.cpp:35: warning: matches this 'x' under old rules autostrazi.cpp:45: warning: comparison between signed and unsigned integer expressions autostrazi.cpp:47: warning: comparison between signed and unsigned integer expressions autostrazi.cpp:46: warning: 'son1' may be used uninitialized in this function autostrazi.cpp:48: warning: 'son2' may be used uninitialized in this function