/in/foo.cc: In function 'int main()':
/in/foo.cc:17:14: error: 'n' was not declared in this scope
  scanf("%d",&n);
              ^
/in/foo.cc:18:6: error: 'i' was not declared in this scope
  for(i=1;i<=n;i++)
      ^
/in/foo.cc:23:22: error: 'memcpy' was not declared in this scope
  memcpy(b,a,sizeof(a));
                      ^
/in/foo.cc:24:20: error: 'sort' was not declared in this scope
  sort(a+1,a+1+n,cmp);
                    ^
/in/foo.cc:25:6: error: 'i' was not declared in this scope
  for(i=1;i<=n;i++)
      ^
/in/foo.cc:29:6: error: 'i' was not declared in this scope
  for(i=1;i<=n;i++)
      ^