Compilare: user.cpp: In function ‘int main()’: user.cpp:49:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 0; i < nrE; ++i) ^ user.cpp:63:52: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 2; i <= n; ++i) printf("%d ", costs[i]!=-1 ? costs[i]:0); ^ user.cpp:26:36: 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:27:38: 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:32:23: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &n, &m); ^ user.cpp:36:41: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d", &source, &dest, &cost); ^