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42 ob.read();
43 ob.printlong();
44 }
45 }
The output of the preceding program is as follows:
Enter a sentence
Saturn, Mars, and Earth are planets in our solar system.
Longest word is
planets
If more than one word has the highest length, which means two or more words have the same length, then the
preceding program would return all the words having the highest length.
12.3 DATA FILE HANDLING
Till now, we have used variables to store values. These values gets lost when a program’s execution is stopped.
Sometimes, we face a situation in which we need to store a value or several values permanently for future reference.
For example, when an employee joins a particular organisation, the organisation collects data about the employee like
name, father’s name, mother’s name, date of birth, gender, etc. and stores this data in the organisation’s information
system permanently. Similarly, organisation has collected data of thousands of employees. So, to handle large amounts
of data, Java provides the concept of files. The process of handling files is called file handling.
A file is a named location that can be used to store related data permanently in a secondary storage device. Files are
stored in an organised manner in directories. There are different types of files and formats available on computers as
described in the following table.
File Type Description
Image files These files store images or graphics. Image files can be of different
types namely .jpeg, .gif, .png, .tif, .svg, etc.
Document files These files are used to create, edit and print documents. There are
different types of document files like .doc, .pdf, .txt, etc.
Video files These files are stored in file formats like .mp4, .avi, .mov, .flv, etc.
Audio files These files are used to store songs, lectures, etc. in different audio
file formats like .mp3, .wav, etc.
Database files These files store related records in an organised manner. There are
various types of database files like .mdb, .csv, .xls, .sql, .idx, etc.
Program files These files are used to store code written in different programming
languages. There are different types of program files like .java,
.bas, .cpp, .py, etc.
Data files are the files that contain data in the form of records. A record is further divided into fields. Data files are
non-executable files that can be created, read or viewed. In some data files, data is stored in the form of text but some
other data files store data in a more organised manner as records. The different subdivisions are:
• Field: It is the smallest unit of data that can be accessed by a user. It is identified by a unique name called field name.
• Record: It is a collection of related fields.
• File: Files (data files) are a collection of related records.
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