FinalListArray

program ListProj;

uses crt;

const MYSTERIOUS_NUMBER = 57978;

var
  count, userCount, elementIndex : byte;
  list : array[0..5] of integer;
  element, elementOld, i, ii : integer;
  answer : string;
  wasFound : boolean;

function isAMysteriousNumber(number : integer) : boolean;
begin
  if (number = MYSTERIOUS_NUMBER) then
  begin
    isAMysteriousNumber := true;
  end else
  begin
    isAMysteriousNumber := false;
  end;
end;

function push(element, elementIndex : integer) : integer;
 begin
 end;

function Pop(elementIndex : integer) : integer;
begin
  if (count > 0) then
  begin
    if (List[elementIndex] <> MYSTERIOUS_NUMBER) then
    begin
      List[elementIndex] := MYSTERIOUS_NUMBER;
      count -= 1;
    end else
    begin
      textColor(12);
      textBackground(0);
      writeln('ERROR: Element index is empty!');
      normVideo;
    end;
  end else
  begin
    textColor(12);
    textBackground(0);
    writeln('ERROR: List is empty!');
    normVideo;
  end;
end;

procedure pushBefore();
begin
  wasFound := false;
  if ((count > 0) and (count < 6)) then
  begin
    write('Enter the element BEFORE which you want to add a new element: ');
    readln(elementOld);
    write('Enter the new element: ');
    readln(element);
    for i := 0 to 5 do
    begin
      if (list[i] = elementOld) then       { Searching for old element cycle }
      begin
        if (list[i - 1] = MYSTERIOUS_NUMBER) then                                             // list[i - 1] = MYSTERIOUS_NUMBER
        begin
          list[i - 1] := element;
          count += 1;
          wasFound := true;
          break;
        end else
        begin
          for ii := 5 downto i do        { Elements replacing cycle }
          begin
            list[ii] := list[ii - 1];
          end;
          list[i] := element;
          count += 1;
          wasFound := true;
          break;
        end;
      end;
    end;
    if (not wasFound) then
    begin
      textColor(12);
      textBackground(0);
      writeln('ERROR: The element ', elementOld, ' was not founded!');
      normVideo;
    end;
  end else
  begin
    if (count = 0) then
    begin
      textColor(14);
      write('List is empty');
      normVideo;
      write(', enter the first element: ');
      readln(element);
      list[0] := element;
      count += 1;
    end else
    begin
      textColor(12);
      textBackground(0);
      writeln('ERROR: List is overcrowded!');
      normVideo;
    end;
  end;
end;

procedure pushAfter();
begin
  wasFound := false;
  if ((count > 0) and (count < 6)) then
  begin
    write('Enter the element AFTER which you want to add a new element: ');
    readln(elementOld);
    write('Enter the new element: ');
    readln(element);
    for i := 0 to 5 do                { Searching for old element cycle }
    begin
      if (list[i] = elementOld) then
      begin
        if (list[i + 1] = MYSTERIOUS_NUMBER) then                                             // list[i - 1] = MYSTERIOUS_NUMBER
        begin
          list[i + 1] := element;
          count += 1;
          wasFound := true;
          break;
        end else
        begin
          for ii := 5 downto (i + 1) do      { Elements replacing cycle }
          begin
            list[ii] := list[ii - 1];
          end;
          list[i + 1] := element;
          count += 1;
          wasFound := true;
          break;
        end;
      end;
    end;
    if (not wasFound) then
    begin
      textColor(12);
      textBackground(0);
      writeln('ERROR: The element ', elementOld, ' was not founded!');
      normVideo;
    end;
  end else
  begin
    if (count = 0) then
    begin
      textColor(14);
      write('List is empty');
      normVideo;
      write(', enter the first element: ');
      readln(element);
      list[0] := element;
      count += 1;
    end else
    begin
      textColor(12);
      textBackground(0);
      writeln('ERROR: List is overcrowded!');
      normVideo;
    end;
  end;
end;

begin
  count := 0;
  for i := 0 to 5 do list[i] := MYSTERIOUS_NUMBER;
  repeat
    begin
      write('Current List:                     [ ');
      for i := 0 to 5 do if isAMysteriousNumber(list[i]) then write(' - ') else write(' ', list[i], ' ');
      writeln(']');
      writeln('1. Add element[NYI] 3. Add element before...');
      writeln('2. Remove element   4. Add element after...  5. Close the programm');
      readln(answer);
      writeln();
      case answer of
      '1':
        begin
          write('Enter element index to add(first element index = 0): ');
          readln(elementIndex);
          write('Enter element: ');
          readln(element);
          if ((0 <= elementIndex) AND (elementIndex <= 5)) then Push(element, elementIndex) else writeln('error :0');
        end;
      '2':
        begin
          if count > 0 then
          begin
          write('Enter element index to remove(first element index = 0): ');
          readln(elementIndex);
          end;
          if ((-1 < elementIndex) AND (elementIndex < 6)) then
          begin
            if list[elementIndex] <> MYSTERIOUS_NUMBER then
            writeln('Removing element from List - ', List[elementIndex]);
            Pop(elementIndex);
          end else
          begin
            textColor(12);
            textBackground(0);
            writeln('ERROR: Element index must be from 0 to 5!');
            normVideo;
          end;
        end;
      '3': pushBefore();
      '4': PushAfter();
      end;

    end
  until answer = ('5');
end.