Random- Access Files

In the previous sections, you learned how to read and write data to a sequential file. In this section, you will learn how to access random files.

A random file is a file whose data you can read or write in any order without having to read or write all other data.

For example, you can write student records to a random file and then read one or more record later in any order. Before we discuss about random files, we will first discuss about user-defined data type. Random access files often read and write data records, and VB's user defined data types let you define data items that look exactly like the records you need to write to (and read from) the random file.

The following statement opens a file for random access:

Open "Random.txt" For Random As #1

Two statements are used for random access files: Put # and Get #.

Put [#]filenumber, [recnumber], varname
Get [#]filenumber, [recnumber], varname

These statements use a record number. Record numbers begin with 1. The variable you read or write can be of any data type- even an array or a user defined data type.

The freedom to handle any type of variable as a single unit is one of the most powerful features of random access files.