Compilare: user.cpp: In function ‘int main()’: user.cpp:22:17: warning: unused variable ‘w’ [-Wunused-variable] int n,m,u,v,w,d; ^ user.cpp:19:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("dijkstra.in", "r", stdin); ^ user.cpp:20:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("dijkstra.out", "w", stdout); ^ user.cpp:24:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &n, &m); ^ user.cpp:27:35: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d",&u, &v, &d); ^