Write (F, E1, ... , En) is equivalent to the statement 

begin Write(F,E1); ... ;Write(F,En) end 

The advantage of using these procedures lies not only in brevity, but also in conceptual simplicity, since the existence of a buffer variable Fi, which is sometimes undefined, may be ignored. The buffer variable may, however, be useful as a "lookahead" device. 

Examples of declarations 

Examples of statements with files 

var Data: file of Integer; A: Integer; var Plotfile: file of record C: Color; Len: Natural end; var Club: file of Person; P: Person; 

A := Datai; Get (Data) Read(Data,A) Plotfilei.c := Red; Plotfilei.Len := 17; Put (Plotfile) Clubi:= P; Put (C1ub) Write(Club,P) 

Files may be local to a program (or local to a procedure), or they may already exist outside the program. The latter are called external files. External files are passed as parameters in the program heading (see Chapter 3) into the program. 

The next two programs illustrate the use of files. Program 9.1 reprocesses a file of real numbers representing measurements produced by an instrument or another program. Program 9.2 operates on two files 

