Compilare: main.cpp: In function 'int main()': main.cpp:16:27: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen(_fin, "r", stdin); ^ main.cpp:17:28: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen(_fout,"w", stdout); ^ main.cpp:19:48: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] for (scanf("%d%d%d%d", &n, &t1, &t2, &t3), i=1; i<=n; i++) scanf("%d%d", a+i, b+i); ^ main.cpp:19:84: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] for (scanf("%d%d%d%d", &n, &t1, &t2, &t3), i=1; i<=n; i++) scanf("%d%d", a+i, b+i); ^