/in/foo.cc: In function 'int main()':
/in/foo.cc:14:15: error: 'i' does not name a type
  for(register i=1;i<=n;i++)
               ^
/in/foo.cc:14:19: error: expected ';' before 'i'
  for(register i=1;i<=n;i++)
                   ^
/in/foo.cc:14:19: error: 'i' was not declared in this scope
/in/foo.cc:17:8: error: 'k' was not declared in this scope
  ans=0,k=(n+1)/2;
        ^
/in/foo.cc:18:15: error: 'i' does not name a type
  for(register i=1;i<=n;i++)
               ^
/in/foo.cc:18:19: error: expected ';' before 'i'
  for(register i=1;i<=n;i++)
                   ^
/in/foo.cc:18:19: error: 'i' was not declared in this scope