what is the significance of these four lines show below : I found in this complete [code][1] on codeforces . I am not that expert please guide me the use of these lines of code shown below
The question just reads an input string of integers of maximum length 1000
  
     ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0);
    `#ifndef ONLINE_JUDGE  
    `freopen("test.in", "r", stdin); 
    `#endif


  [1]: http://codeforces.com/contest/743/submission/22981724