Compilare: user.cpp: In function ‘bool connected(node*, node*)’: user.cpp:69:11: warning: unused variable ‘b’ [-Wunused-variable] node *b = expose(v); ^ user.cpp: In function ‘int main()’: user.cpp:76:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("disjoint.in", "r", stdin); ^ user.cpp:77:41: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("disjoint.out", "w", stdout); ^ user.cpp:80:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &N, &M); ^ user.cpp:86:41: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d ", &tip, &a, &b); ^