macOS Pascal - Passing a Record as a Param.

[larswik]

So last night I had my last Pascal Class and Monday is the FINAL! I lost my book a month ago and finally got a new one 2 days ago and I am playing catchup.
By Monday I need to have read up on and understand
1. Arrays
2. Multi Dimensional Arrays
3. Records (which sounds like C Structs)

Each of these I get by there own for the most part. But combining them I get lost. Example, passing an ARRAY of RECORDS as a PARAMETER to a PROCEDURE

I was slowly working on some code and compiling as I went along and then hit a snag. I am getting a error in the PROCEDURE on this line Studentcard.idno := 3345; . I am trying to assign that integer value 3345 to the record being stored in that array. I must be over looking something obvious.

program procpass;

const
	numOfRecords = 30;


type
	numOfRecordes = 1..30;
	student = record
				name : char;
				major : integer;
				classtpe : integer;
				idno : integer;
			  end;
	oneRecord = array[numOfRecordes] of student;
	
var

	studentcard : oneRecord;

procedure inputdata(studentcard : oneRecord);
var
	i : integer;
	begin
		for i := 1 to 30 DO
			Studentcard.idno[i] := 3345;
	end;
begin
inputdata(studentcard);

end.

Any help is appreciated

-Lars

 

[McGordon]

You didn't say what the error message said, which should have gave you a hint.

I have only got vague memories of pascal, but here goes...

You have an array of records, so to access a field in the record, you'd have to first access the record i.e. access an element of the array, then access its field.

studentcard[i].idno := 3345;

If its case insensitive, it wouldn't matter whether you use Studentcard or studentcard, but it doesn't look good if you change it every other time.

 

[larswik]

It is case insensitive and the error message I got was 'illegal Qualifier'

Thanks,

-Lars

 

[gnasher729]

It is case insensitive and the error message I got was 'illegal Qualifier'

Would be good to know on which line exactly the error is.

But your code won't work; you pass a record by value, so the global variable will not be modified. You probably want

procedure inputdata (var studentcard : oneRecord);

 

[larswik]

gnasher729 - Thanks, I found that out about 10 minutes ago looking through old notes. The var allows me to pass the address so I can get something out of that procedure.

I also fixed this
Studentcard.idno := 3345;

to this
Studentcard.idno := 3345;

and it works now.

Thanks for your help.

-Lars

 

[Bill McEnaney]

So last night I had my last Pascal Class and Monday is the FINAL! I lost my book a month ago and finally got a new one 2 days ago and I am playing catchup.
By Monday I need to have read up on and understand
1. Arrays
2. Multi Dimensional Arrays
3. Records (which sounds like C Structs)

Each of these I get by there own for the most part. But combining them I get lost. Example, passing an ARRAY of RECORDS as a PARAMETER to a PROCEDURE

I was slowly working on some code and compiling as I went along and then hit a snag. I am getting a error in the PROCEDURE on this line Studentcard.idno := 3345; . I am trying to assign that integer value 3345 to the record being stored in that array. I must be over looking something obvious.

program procpass;

const
	numOfRecords = 30;


type
	numOfRecordes = 1..30;
	student = record
				name : char;
				major : integer;
				classtpe : integer;
				idno : integer;
			  end;
	oneRecord = array[numOfRecordes] of student;
	
var

	studentcard : oneRecord;

procedure inputdata(studentcard : oneRecord);
var
	i : integer;
	begin
		for i := 1 to 30 DO
			Studentcard.idno[i] := 3345;
	end;
begin
inputdata(studentcard);

end.

Any help is appreciated

-Lars

The problem is probably that idno isn't an array. It's a component of an element of an array. Try:

Studentcard[i].idno := 3345;

Or,

with Studentcard[i] do
   idno := 3345;