Can anyone give me an example for crm_svy_..._pai?

Hi all, I have a survey, there are several questions. After I input the answers, I click the 'CHECK' button, I will check the answers. There will be different response to my answers. If the answer is not correct, I will post an error message.

And I also need to retrieve data from tables to fill the blank.

I am a beginner for CRM survey, can anyone help me? I create a FM:crm_svy_..._pai, and code in it right? But how can I do it?

Can anyone give me an example for crm_svy_..._pai to do what I need?

Many many thanks in advance!!

Heare is an example, but I don't its function and how does it work..

read table lt_all_values into ls_value

with key answer_id = 'get_value'.

if sy-subrc = 0.

data: lt_values type crm_svy_api_string_t.

append ls_value-value to lt_values.

call method ir_survey_values->values_set

exporting

i_question_id = 'set_value'

i_answer_id = 'set_value'

it_values = lt_values.

endif.