Compilare: user.cpp: In function ‘int main()’: user.cpp:44:9: warning: unused variable ‘j’ [-Wunused-variable] int i, j, a, b, c, vertex, selectedVertex; ^ user.cpp:48:31: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("apm.in", "r", stdin); ^ user.cpp:49:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("apm.out", "w", stdout); ^ user.cpp:50:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &n, &m); ^ user.cpp:53:146: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] for (i = 1; i <= m; i++) scanf("%d%d%d", &a, &b, &c), tree[a - 1].push(*new edge(a - 1, b - 1, c)), tree[b - 1].push(*new edge(b - 1, a - 1, c)); ^