update BuddyPress xprofile programmatically

gistfile1.php

<?php 
function smc_update_xprofile($userid,$field,$value) {
    // alternative to get user ID
    // global $current_user;
    // get_currentuserinfo();

    // $field = 'Foo'; // xProfile field name
    // $value = 'bar'; // desired value

    // xprofile_set_field_data($field, $current_user->id,  $value);
    xprofile_set_field_data($field, $userid,  $value);

}