## CHAPTER 9 

## File Types 

In many ways the simplest struCtli ring method is the sequence. In the data-processing profession the generally accepted term to describe a sequence is a sequentialfile. Pasc,d uses simply the wordfile to specify a structure consisting of a sequencl: of components - all of which have the same type. A special kind 01 file called a textfile consists of a sequence of variable-length lines of characters and forms the basis for legible communications between people and computer systems. 

## 9.A. The File Structure 

A natural ordering of the com pont' nts is defined through the sequence, and at any instance only one component is directly accessible. The other components are accessible II)' progressing sequentially through the file. The number of componell''i, called the length of the file, is not fixed by the file-type definition. This is a characteristic which clearly distinguishes the file from the arra~ A file with no components is said to be empty. A file type, therefore, dill'ers from array, record, and set types because it is a sequential-access Si ructure whose components all have the same type. 

