Compilare: user.cpp: In function ‘int main()’: user.cpp:47:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &n, &m); ^ user.cpp:49:60: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] Edge e; scanf("%d%d%d%d", &e.x, &e.y, &e.c1, &e.c2); ^