/in/foo.cc:1:1: error: 'include' does not name a type
 include<bits/stdc++.h>
 ^~~~~~~
/in/foo.cc: In function 'int main()':
/in/foo.cc:6:5: error: 'cin' was not declared in this scope
     cin>>n;for(int i=1;i<=n;i++)cin>>a[i];
     ^~~
/in/foo.cc:9:20: error: 'swap' was not declared in this scope
     {swap(a[x],a[y]);x++,y--;}
                    ^
/in/foo.cc:10:26: error: 'cout' was not declared in this scope
     for(int i=1;i<=n;i++)cout<<a[i]<<" ";   
                          ^~~~