How to allow users to edit item of a column in sharepoint list depending on logins

hi,
 I have a sharepoint list  test..in this i have 2 columns status{Approve,Reject}
 cancel{yes,no}.. i want only users with full control permission edit the status column and users created the item can edit the cancel column...in edit form both columns must be visible..depending on login/pemissions they have to edit the items... i worked out using sharepoint desinger..but using object model can any one help