convert string to date in Lazarus Pascal - pascal

Question

I am much of a new bee to Pascal programming I have spent the entire day trying to convert a string to a valid date that I can later use to subtract another date from to discover the number of days between the two dates. Can you pls pls help me.
I started with this code to try to convert the first date entered in string format to a date that can be used in a calulation:
program TryDate;
Var
date1: TDateTime;
thedate:string;
Begin
Writeln ('Enter date');
Readln (thedate);
date1:=StrToDate (thedate);
Writeln ('The date is ',date1);
end.
The program's basic structure can be seen here:
Begin
Writeln ('Enter customer last name');
readln (clname);
Writeln ('Enter customer first name');
readln (cfname);
Writeln ('Enter Dvd Title');
readln (dvdtit);
Writeln ('Enter Due Date');
readln (dued);
Writeln ('Enter Actual Date Returned');
readln (adret);
daysover:=adret-dued;
readln;
end.
I am expected to expand the program further but was trying to get this small part to work before trying the other components.
Simple instructions and examples or possible solutions will be greatly appreciated.

Answer 1

You haven't specified what the issue with the code you've got so far is. The only issue I can see, if your actual code is exactly like what you've posted, is that you haven't specified uses sysutils;, like this:
program TryDate;
uses
sysutils;
Var
date1: TDateTime;
thedate: string;
Begin
Writeln ('Enter date');
Readln (thedate);
date1 := StrToDate (thedate);
Writeln ('The date is ',date1);
end.
The StrToDate function is part of the sysutils unit, which you need to include in your program through uses to be able to use its procedures, functions, types etc.

Answer 2

In addition to Andriy, you also don't supply OS information, or what format you enter the date.
This is important because on *nix you have to add clocale to your USES clause to initialize locale systems which also include prefered dateformat.
For really scary stuff there is the function scandatetime that can parse most custom created dates: http://www.freepascal.org/docs-html/rtl/dateutils/scandatetime.html