Question

How to combine 2 arrays of records (as a map) into a third array in Pascal

Answer 1

program CombineMapsDemo;

type
  TMapEntry = record
    Key: string;
    Value: string;
  end;

const
  MaxSize = 64;

var
  Map1, Map2, Combined: array[1..MaxSize] of TMapEntry;
  Size1, Size2, Size_Combined: integer;
  i, j: integer;
  found: boolean;

procedure InitializeMaps;
begin
  // Initialize Map1
  Size1 := 2;
  Map1[1].Key := 'A'; Map1[1].Value := 'AAA';
  Map1[2].Key := 'B'; Map1[2].Value := 'BBB';

  // Initialize Map2
  Size2 := 2;
  Map2[1].Key := 'C'; Map2[1].Value := 'CCC';
  Map2[2].Key := 'B'; Map2[2].Value := 'XYZ';  // Overwrites key 'B'
  Map2[2].Key := 'D'; Map2[2].Value := 'DDD'; 
end;

procedure CombineMaps;
begin
  Size_Combined := 0;

  // Copy Map1 into Combined
  for i := 1 to Size1 do
  begin
    inc(Size_Combined);
    Combined[Size_Combined] := Map1[i];
  end;

  // Merge Map2 into Combined, overwriting duplicates
  for i := 1 to Size2 do
  begin
    found := false;
    for j := 1 to Size_Combined do
    begin
      if Combined[j].Key = Map2[i].Key then
      begin
        Combined[j].Value := Map2[i].Value; // Overwrite value
        found := true;
        break;
      end;
    end;
    if not found then
    begin
      inc(Size_Combined);
      Combined[Size_Combined] := Map2[i];
    end;
  end;
end;

procedure DisplayCombined;
begin
  writeln('Combined Arrays:');
  for i := 1 to Size_Combined do
    writeln(Combined[i].Key, ' => ', Combined[i].Value);
end;

begin
  InitializeMaps;
  CombineMaps;
  DisplayCombined;
end.




(*
run:

Combined Arrays:
A => AAA
B => BBB
C => CCC
D => DDD

*)

 

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