change.pas

关于课件 好多种结构的算法 等等 大家自己看吧

program change(input,output,g);
type
 Repltp=integer ;
 fltp=file of Repltp ;
var
 m:Repltp ; 
 g:fltp ;
 data:string ; 
Procedure Repl(var f:fltp ;  n:Repltp);
 var  
  x,y:Repltp ;
  fg:boolean ;
 begin
  fg:=false;
  while not eof(f) and (fg=false) do
   begin
    read(f,x);
    if x=n then
      begin
       write('input data you want to replace ',n,'  ');
       read(y) ;
       seek(f,filepos(f)-1);
       write(f,y);
       fg:=true;
      end ;
    end ;
 end;
 Procedure scan(var f:fltp);
 var
   x:integer;
 begin
   while not eof(f) do
    begin
     read(f,x);
     write(x:6);
    end;
   writeln;
 end ;
 begin
  data:='chngfile';
  assign(g,data);
  reset(g);
  scan(g);
  reset(g);
  write('input data you want to replace ');
  readln(m);
  Repl(g,m);
  reset(g);
  scan(g);
  close(g);
 end .