Objects with logic + arrays of objects — Information Technology

Grade 12 · Object-oriented programming · Lesson and coding task · about 18 minutes

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Real exam questions give methods decisions to make. A method can use IFs, loops — anything — on its own fields:

function TLearner.GetStatus : String;
begin
  if GetAverage >= 50 then
    Result := fName + ': ' + FloatToStrF(GetAverage, ffFixed, 6, 1) + '% (PASS)'
  else
    Result := fName + ': ' + FloatToStrF(GetAverage, ffFixed, 6, 1) + '% (FAIL)';
end;

And the final boss pattern: an array of objects. The starter's FormCreate builds four TLearner objects into arrLearners. Loop over them exactly like an array of numbers — each element just happens to be an object:

for i := 1 to 4 do
  memOutput.Lines.Add(arrLearners[i].GetStatus);

Your task

Implement GetStatus, then loop over the array to report every learner, count the passes (average ≥ 50) and the distinctions (average ≥ 80).

What you will do

Implement GetStatus with the PASS/FAIL decision (average >= 50 passes)
Loop over arrLearners showing each learner's status line
Count passes and distinctions (>= 80) and end with: Passed: 3 then Distinctions: 1

Hints

GetStatus is an IF on GetAverage — both branches build the same string, only (PASS)/(FAIL) differs.
In the loop, arrLearners[i].GetStatus and arrLearners[i].GetAverage work exactly like any method call.
Initialise both counters to 0 before the loop; add the two summary lines after it.

Model solution

type
  TLearner = class
  private
    fName : String;
    fMark1, fMark2 : Integer;
  public
    constructor Create(sName : String; iM1, iM2 : Integer);
    function GetAverage : Real;
    function GetStatus : String;
  end;

constructor TLearner.Create(sName : String; iM1, iM2 : Integer);
begin
  fName := sName;
  fMark1 := iM1;
  fMark2 := iM2;
end;

function TLearner.GetAverage : Real;
begin
  Result := (fMark1 + fMark2) / 2;
end;

function TLearner.GetStatus : String;
begin
  if GetAverage >= 50 then
    Result := fName + ': ' + FloatToStrF(GetAverage, ffFixed, 6, 1) + '% (PASS)'
  else
    Result := fName + ': ' + FloatToStrF(GetAverage, ffFixed, 6, 1) + '% (FAIL)';
end;

var
  arrLearners : array[1..4] of TLearner;

procedure TfrmClass.FormCreate(Sender: TObject);
begin
  arrLearners[1] := TLearner.Create('Thabo', 78, 71);
  arrLearners[2] := TLearner.Create('Anele', 90, 85);
  arrLearners[3] := TLearner.Create('Pieter', 55, 40);
  arrLearners[4] := TLearner.Create('Fatima', 82, 77);
end;

procedure TfrmClass.btnReportClick(Sender: TObject);
var
  i, iPassed, iDistinctions : Integer;
begin
  iPassed := 0;
  iDistinctions := 0;
  for i := 1 to 4 do
  begin
    memOutput.Lines.Add(arrLearners[i].GetStatus);
    if arrLearners[i].GetAverage >= 50 then
      Inc(iPassed);
    if arrLearners[i].GetAverage >= 80 then
      Inc(iDistinctions);
  end;
  memOutput.Lines.Add('Passed: ' + IntToStr(iPassed));
  memOutput.Lines.Add('Distinctions: ' + IntToStr(iDistinctions));
end;

Your task

What you will do

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