desen.cpp: In function 'int main()': desen.cpp:65: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result desen.cpp:66: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result desen.cpp:68: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result desen.cpp:78: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result desen.cpp: In function 'void Kruskal(int)': desen.cpp:106: warning: comparison between signed and unsigned integer expressions