Unit file structure

Unit unit1; interface {Interface part start} uses {reference unit list, this is optional. If the list contains a constant/type/variable/process and function that must follow the interface keyword} {the Interface part declares the constant/type/variable/process and function, these declarations are just like your own Declarations} {processes and functions declared in the interface section, like using the forward keyword} {Interface part end} implementation {implementation part} uses {if it contains the uses sentence, must keep up with the keyword Implementation} {the processes and functions defined in the interface can be defined and called in any order .} {The process and function list can be omitted here. If included, the process and function list must be the same .} {constants/types (including classes), variables/procedures, and functions that are private to a unit can be defined, but they are invisible to customers who reference the unit.} {$ R *. DFM} {if it is a unit file of the corresponding form, this sentence will appear. $ R command is used to load an external resource file, which is used to load a Form file with the same name for compilation .} initialization {initialization part }{ProgramExecute first when starting, and execute in sequence} {initialization of a UnitCodeBefore running, it runs the initialization part of every unit it uses} finalization {finalization part, and execution at program end} end.