Compilare: user.cpp: In function ‘int main()’: user.cpp:254:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("vis.in", "r", stdin); ^ user.cpp:255:68: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d %d %d %d %d", &n, &k1, &k2, &l1, &c1, &l2, &c2); ^ user.cpp:257:58: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] for(int j = 1; j <= n; ++j) scanf("%d", &a[i][j]); ^