foo.cpp:1:1: error: 'include' does not name a type
 include<iostream>
 ^
foo.cpp: In function 'int main()':
foo.cpp:10:1: error: 'cin' was not declared in this scope
 cin>>n;
 ^
foo.cpp:16:15: error: 'swap' was not declared in this scope
 swap(a[i],a[j]);
               ^
foo.cpp:25:1: error: 'cout' was not declared in this scope
 cout<<ans;
 ^