What is the use of clear statement? | SAP-ABAP

=>    Internal tables are initialized using clear statement. It is used to either delete all rows from an internal table or clear the header line.
The syntax of clear statement is as follows:
   clear<itab>  clear<itab>[]
<itab> is a header line and <itab>[] is a body of the table .
clear <itab>: It clears the header line of the internal table. If <itab> does not have a header line, it will delete the body of the internal table.
clear <itab>[]: It deletes the body of the internal table and header line is unchanged. In both methods, the memory remains allocated.