Selection-screen output , initialaization confusion

Question

we have selectionscreen output, initialization events
first initializatuion,
than at selection-screen output
execute it, than we pressed f3 came bact  to  selection-screen
than which event  ll trigger
thank you
kals.

Answer 1

The different events in a report Program are:
Load-of-program
Triggers the associated event in an internal session after loading a program of type 1, M, F, or S. Also runs the associated processing block once and once only for each program and internal session. The processing block LOAD-OF-PROGRAM has roughly the same function for an ABAP program of type 1, M, F or S as a constructor has for classes in ABAP Objects
Initialization.
This event is executed before the selection screen is displayed .
Initialization of all the values.
You can assign different values other than the values defaulted on the selection screen .
You can fill your selection screen with some values at runtime.
At Selection-Screen.
The event is processed when the selection screen has been processed (at the end of PAI ).
Validation & Checks of inputted values happen here
Extras :
…ON VALUE-REQUEST FOR psel_low_high .
The pushbutton for F4 (Possible entries) appears beside the appropriate field.
... ON HELP-REQUEST FOR psel_low_high
. ... OUTPUT
This event is executed at PBO of the selection screen every time the user presses ENTER
Start-of-Selection.
Here the program starts selecting values from tables.
End-of-selection.
After all the data has been selected this event writes the data to the screen.
Interactive Events
Used for interactive reporting. It is used to create a detailed list from a basic list.
Events in an ABAP/4 Report Program
Start-Of-Selection
Processing block is executed after processing the selection screen
All the data is selected in this block.
All the main processing on the data except for interactive reporting is handled in this block.
End-Of-Selection
Data which is selected and has been processed is printed to the screen in this block.
List Processing happens in this block
Top-of-Page.
New-Page.
End-of-Page.
Events during List Processing
Top-of-Page.
Triggered by the first write statement in the program
It is used to have a standard header in the program for all the pages.
TOP-OF-PAGE is only executed before outputting the first line on a new page
New-Page.
Can be used when one wants to display different data on different pages
Terminates the current page and continues output on a new page.
Will not trigger the Top-of-Page or End-of-Page.
End-of-Page.
It is used to have a standard footer for all the pages.
Triggered by the program if the number of records exceed the line-count of the program.
Hope u understood....