INDEXED SEQUENTIAL FILES:
In the indexed sequential files which are also known as indexed files, the records are stored in the sequence order generally in ascending order. In addition, some of the index tables are also created and maintained with the file.
An indexed file on COBOL can be accessed either sequential or randomly. Though, while creating an indexed file the records can be written only sequentially and in the ascending order of the key. Whenever an indexed file is accessed randomly, the series in which the records are accessed is controlled by the programmer by specifying the value of the data item known as record key.
The Indexed files in a COBOL program can be handled through appropriate special codes in the FILE-CONTROL paragraph and in the PROCEDURE DIVISION.