What is difference between random file access and sequencial flle access in c?

File constructed in a manner in which records may be placed in a random order; also called direct access file. Each record in a random access file has associated with it a relative index number. Whenever a record is read from a random access file, a computer program must produce a relative index number for this record in order to locate the record in the file. This type of file design offers the following
advantages:
(1) it provides rapid access to the desired information. In a decision-making environment where information is needed quickly, random access is a requisite to rapid retrieval;
(2) it is efficient for retrieving a relatively few records at a time; and
(3) it provides a method of keeping files up to date as transactions or events occur