Compilare: user.cpp: In function ‘void read_data()’: user.cpp:19:30: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ("%d%d%d", &N, &M, &K); K --; ^ user.cpp:21:51: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ("%d%d%d", edg[i], edg[i] + 1, edg[i] + 2); ^ user.cpp: In function ‘int main()’: user.cpp:119:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("bcolor.in", "rt", stdin); ^ user.cpp:120:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("bcolor.out", "wt", stdout); ^