CHAPTER 9  File Types  9.A.  The File Structure  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.  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. 