Compilare: user.cpp: In function ‘void kruskal()’: user.cpp:75:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i = 0 ; i < Edge.size(); i++) { ^ user.cpp: In function ‘void read()’: user.cpp:36:30: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen(FIN, "r", stdin); ^ user.cpp:38:44: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &num_nodes, &num_edges); ^ user.cpp:42:42: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d", &X, &Y, &Cost); ^ user.cpp: In function ‘void write()’: user.cpp:96:31: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen(FOUT, "w", stdout); ^