{*write a pascal program to keep record of examination marks of 45 students.
In the program, validate the input of marks so that the marks should not include character
and the range of marks is 0 to 100*}

(*Techniques : Validation of inputting data is the best to use REPEAT loop, all the conditions should be
             fulfilled before the execution can jump out of the loop. String variable must be used so that the length
             can be checked by length( ) function, characters can be checked by VAL procedure. In other words
             data of an unexpected type will be rejected until the right type to be accepted. *)

{*Winnie Leung  F.4CA (22) *}
program Valide_mark;
uses wincrt;
var mark:array[1..45] of string;
    i, er, marks : integer;
begin
     i := 1;
     repeat
           repeat
           writeln('No:', i);
           write('Marks: ');
           readln(mark[i]);
           Val(mark[i], marks, er);

           until (er=0) and ((marks>-1) and (marks<101));
           i:=i+1;
     until i>5;
     writeln('No. Marks');
     For i := 1 to 5 do
        writeln(i, '    ', mark[i]);
end.