Compilare: user.cpp: In function ‘void read()’: user.cpp:28:35: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d", &n, &m, &g); ^ user.cpp:33:41: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] cost[x][y] = cost[y][x] = z; ^ user.cpp: In function ‘int main()’: user.cpp:82:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("trafic.in", "r", stdin); ^ user.cpp:83:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("trafic.out", "w", stdout); ^