recordexample3.pas

学生的姓

program RecordExample(input,output);

Const
	FIRST_NAME_MAX  = 30;
	LAST_NAME_MAX	= 30;
	MAX_STUDENTS	= 100;


Type
	First_Name_Type 	= array[1..FIRST_NAME_MAX] of char;
	Last_Name_Type		= array[1..LAST_NAME_MAX] of char;

	Student_Record_Type	= Record
		Fname	: First_Name_Type;
		Lname	: Last_Name_Type;
		Id		: integer;		
		Gpa		: real;
	end; 

	Student_Collection_Type = array[1..MAX_STUDENTS] 
									of Student_Record_Type;

var
	Debug : boolean;


procedure Display_Record(Student : Student_Record_type; 
					recordno : integer);
Begin
	with Student do
	Begin
		writeln('----------------------------');
		writeln('      Record# ',recordno);
		writeln('----------------------------');	
		writeln('First Name: ':15, Fname);
		writeln('Last Name: ':15, Lname);
		writeln('Id: ':15, Id);
		writeln('GPA: ':15, Gpa:0:2);
		writeln;
	End;
End;

procedure Initialize_Collection(var Students : Student_Collection_Type);
Begin
	var i : integer;

	for i := 1 to MAX_STUDENTS do
	with Students[i] do
	Begin	
		Fname := 'XXXXXXXXX';
		Lname := 'YYYYYYYYY';
		Id := 999999;
		Gpa := 9.9;
	end;
End;


Procedure Display_Collection(var Students : Student_Collection_Type;
								n : integer);
Begin
	var i : integer;

	for i:=1 to n do
		Display_Record(Students[i],i);

end;

procedure Read_Collection(var database : Student_Collection_Type;
							var record_count : integer);
Begin
	var data_file : Text;

	record_count:=0;

	reset(data_file,"students.dat");

	while  not EOF(data_file) do
	Begin
		{*************** Read one record *************}
		record_count:=record_count + 1;
		if debug then writeln('Reading record....',record_count);
		with database[record_count] do
		Begin
			Readln(data_file,fname);
			Readln(data_file,lname);
			Readln(data_file,Id);
			Readln(data_file,Gpa);
			Readln(data_file);
		end;
	end;

	close(data_file);

End;

procedure Search_GPA(var database:Student_Collection_Type;
					total_records : integer; key_GPA : real);
Begin
	var i : integer;
	var found : integer;

	found :=0;

	for i:=1 to total_records do
	begin
		if (database[i].Gpa>=key_GPA) then
		begin
			Display_Record(database[i],i);
			found:=found+1;
			{break;} 
			{**** Add when you only want to extract one record ***}
		end;
	end;
	
	if found=0 then 
		writeln('No record found...')
	else
		writeln(found, " records found...");
End;


begin
	var A : Student_Collection_Type;
	var i : integer;
	var n : integer;

	debug:=true;


	if debug then writeln('Initializing...');
	Initialize_Collection(A);

	if debug then writeln('Reading from file...');
	Read_Collection(A,n);

	
	if debug then writeln('Now Displaying');
	Display_Collection(A,n);

	writeln;
	writeln("*****************************");
	writeln(" Displaying GPA >= 3.3");
	writeln("*****************************");
	search_GPA(A,n,3.3);

end.