I need to create an array within a register that is a sequence of natural numbers, these are inserted by the user and cannot be repeated. My problem is sorting the array values as they are inserted in ascending order. I have tried this code without success. Thank you.
const
MAX = 10;
type
Natural = 0..MAXINT;
Secuencia = RECORD
valores : ARRAY [1..MAX] OF Natural;
tope : 0..MAX;
END;
TipoResultado = (Fallo, Creado, Agregado);
Resultado = RECORD
CASE quePaso : TipoResultado OF
Fallo: ();
Creado: ();
Agregado: (posicion: Natural);
END;
//Non-repeating value search function in array
Function BLineal(valor: Natural; sec: Secuencia ): boolean;
var i : integer;
begin
i := 1;
while (i <= sec.tope) and (sec.valores[i] <> valor) do
i := i + 1;
BLineal := i <= sec.tope
end;
Procedure to order values within the arrangement from smallest to largest by insertion.
//Procedure ORDER
Procedure OrdIns (var sec: Secuencia);
var
i,j: integer;
aux: Natural;
begin
for i := 2 to sec.tope do begin
j := i;
while (j >= 2) and ((sec.valores[j]) < (sec.valores[j-1])) do
begin
aux:=sec.valores[j-1];
sec.valores[j-1]:=sec.valores[j];
sec.valores[j]:=aux;
j := j - 1
end
end;
end;
Do the problem in two steps. First, create a binary tree and insert values as entered. Then when no more values are found simply walk the tree and create the array.
Related
I've run into a bit of a wall with my sorting, I managed to sort the rows of my string grid from smallest to largest but now I'm not sure how to sort it in descending order. I've tried using the code I used from the other sort and I only changed the 2nd last loop in the code to see if I can read from the bottom of the TStringList, but it hasn't worked and only takes one row from the list and duplicates it into the rest of the rows. Is there perhaps a way to reverse read a TStringList after sorting?
Code I used for the other sort I have and tried to implement for this sort (only changed the 2nd last loop):
procedure TfrmPuntehou.SortLTSGrid(var grid: TStringGrid; columntotal: Integer);
const
separator = ',';
var
iCount,i,j,k,iPos:integer;
TheList:TStringList;
sString,sTempString:string;
m: Integer;
o: Integer;
begin
//procedure to sort from large to small values
//get row amount
iCount:=grid.RowCount-1;
//create list
TheList:=TStringList.Create;
TheList.Sorted:=False;
//start of try..finally block
try
begin
//fill the list
for i := 1 to (iCount - 1) do
begin
TheList.Add(grid.Rows[i].Strings[columntotal]+separator+grid.Rows[i].Text);
end;
//sort the list
TheList.Sort;
for k := 1 to TheList.Count do
begin
//take the line of the list and put it in a string var
sString:= TheList.Strings[(k-1)];
//get separator pos in that string
iPos:=AnsiPos(separator,sString);
sTempString:='';
//remove separator and the column text at the front of the string
sTempString:=Copy(sString,(iPos+1),Length(sString));
TheList.Strings[(k-1)]:= '';
TheList.Strings[(k-1)]:= sTempString;
end;
//fill the grid
for j:= (iCount - 1) downto 1 do
begin
for o := 1 to (iCount - 1) do
begin
grid.Rows[j].Text := TheList.Strings[(o-1)] ;
end;
end;
//fill the row numbers
for m := 1 to iCount do
begin
grid.Cells[0,m]:= IntToStr(m);
end;
end;
finally
TheList.Free;
end;
//end of try..finally block
end;
Thanks in advance for the help!Kind RegardsPrimeBeat
Use TStringList.CustomSort to sort the list using a specific method for comparison.
The specification for the comparer is given here.
Example:
function Compare1( // Normal alphanum sort
List : TStringList;
Index1 : Integer;
Index2 : Integer) : Integer;
begin
if List[Index1] = List[Index2] then
Result := 0
else if List[Index1] < List[Index2] then
Result := -1
else
Result := 1;
end;
function Compare2( // Reverse alphanum sort
List : TStringList;
Index1 : Integer;
Index2 : Integer) : Integer;
begin
if List[Index1] = List[Index2] then
Result := 0
else if List[Index1] < List[Index2] then
Result := 1
else
Result := -1;
end;
procedure TForm1.Button1Click(Sender: TObject);
var
SList : TStringList;
S : String;
begin
SList := TStringList.Create;
try
SList.Add('Pierre');
SList.Add('Albert');
SList.Add('Paul');
SList.Add('Jean');
SList.Add('Simon');
Memo1.Lines.Add('=== Compare1 ===');
SList.CustomSort(Compare1);
for S in SList do
Memo1.Lines.Add(S);
Memo1.Lines.Add('=== Compare2 ===');
SList.CustomSort(Compare2);
for S in SList do
Memo1.Lines.Add(S);
finally
SList.Free;
end;
end;
I am trying to verify all elements of an array[1..199] if there are negative elements. This code doesn't verify first element of the array. I am obliged to do this by recursive method.
I tried to do a separate condition, but this didn't worked. I firstly made it with for and then changed to recursive method.
Var a:array[1..100] of integer;n:integer;
Function E(n:integer):boolean;
Begin
if n=0 then E:=False
else if a[n]<0 then E:=True
else E:=E(n-1);
End;
Begin
readln(n);
for i:=1 to n do
readln(a[i]);
writeln('Are there negative numbers in array? ',E(n));
readln();
End;
I expect the output true if there are any negative elements or false if there not.
I am not a Pascal expert but I think you are looking for something like this:
program Hello;
var
arrayWithNegatives : array[1..10] of integer = (-1,20,30,40,50,60,71,80,90,91);
arrayWithPositives : array[1..10] of integer = (0,20,30,40,50,60,71,80,90,91);
emptyArray : array of integer;
Function HasNegativeNumbers(a: array of integer; n:integer):boolean;
Begin
if n < 0 then HasNegativeNumbers := False
else if a[n] < 0 then HasNegativeNumbers := True
else HasNegativeNumbers := HasNegativeNumbers(a, n - 1);
End;
begin
writeln (HasNegativeNumbers(arrayWithNegatives, length(arrayWithNegatives) - 1));
writeln (HasNegativeNumbers(arrayWithPositives, length(arrayWithPositives) - 1));
writeln (HasNegativeNumbers(emptyArray, length(emptyArray) - 1))
end.
I have a program that stores the last three recent scores of a game. However, I would like to store only the best scores. Eg. Recent Scores: Tom - 12, Sam - 14, Sue - 16. If i played the game and got a new score of 20, i would like it to store the new score of 20 (with name) and the other two scores of Sam and Sue ...thereby losing Tom. (I'm not worried about order).
Const NoOfRecentScores = 3;
TRecentScore = Record
Name : String;
Score : Integer;
End;
TRecentScores = Array[1..NoOfRecentScores] of TRecentScore;
Var
RecentScores : TRecentScores;
When i play the game, i call a procedure called UpdateRecentScores. Here it is:
Procedure UpdateRecentScores(Var RecentScores : TRecentScores; Score : Integer);
Var
PlayerName : String;
Count,count2 : Integer;
FoundSpace : Boolean;
MinMark,position: Integer;
ScorePresent:boolean = false;
Begin
PlayerName := GetPlayerName;
FoundSpace := False;
Count :=1;
While Not FoundSpace And (Count <= NoOfRecentScores)
Do If RecentScores[Count].Name = ''
Then FoundSpace := True
Else Count := Count + 1;
Here is the part i am struggling with. If no score is previously entered, then i have to accept that the first entered score is going to be the minimum:
If ScorePresent = False then
begin
MinMark:=Score;
ScorePresent:=True;
RecentScores[Count].Name := PlayerName;
RecentScores[Count].Score := Score;
writeln('Minimum Mark is: ',MinMark);
end
...the problem with the above, however, is that if the first score is a very high score, that becomes my minimum score!
Below, i am simply saying that if the Score achieved is greater than the MinMark (i.e. the minimum score) then the score should be stored in the array.
else if Score> MinMark then
begin
For count:= 1 to NoOfRecentScores do
begin
if RecentScores[count].score<Score then
position:=count;
RecentScores[position].Name := PlayerName;
RecentScores[position].Score := Score;
end;
End;
end;
As you can see, i am trying to check what the MinMark is first of all. Then, compare the score that i've just got with the MinMarker to see if it should be stored.
To clarify therefore, I want to save the best 3 scores and not recent scores.
To store n best scores, it is convenient to order them from high to low.
Let us go with an example first. Suppose you have the following four records: Tim - 14, Susan - 7, Don - 5, and Derek - 12. Then the array will look like [('Tim', 14), ('Derek', 12), ('Susan', 7), ('Don', 5)].
Now, what happens when Bert achieves a score of 9? Turns out we just want to insert a pair in a sorted array, so that it becomes [('Tim', 14), ('Derek', 12), ('Bert', 9), ('Susan', 7), ('Don', 5)]. After that, we drop the last element.
If we have to modify the array in place, we find the position pos where to insert Bert (it is position 3), then move everything in positions pos..(n-1) into positions (pos+1)..n, and after that, write Ben and his score to position pos.
Since you're using such a small array (3 records), it's relatively simple. (If your array was considerably larger, you'd want to keep it sorted and use a faster means of locating the right position for it, but your array is extremely small.)
Let's say you now have three RecentScore records, containing Tim - 14, Susan - 7, Derek - 12.
You need to find out if there's a score lower than the one the user just attained by Gemma (9) which is in the CurrentScore record (type TRecentScore), and if so replace it with Gemma's name and score.
Here's a working console project (compiled and run in XE5):
program Project1;
{$APPTYPE CONSOLE}
{$R *.res}
uses
System.SysUtils;
type
TRecentScore = record
Name: string;
Score: Integer;
end;
TRecentScores = array of TRecentScore;
// Function to find lower score than the one we're trying to add.
// Returns the index of the next lower item if there is one, or
// -1 if there isn't one.
function FindLowerScore(Scores: TRecentScores; CheckScore: Integer): Integer;
var
i: Integer;
MinScore: Integer; // Lowest score found
begin
Result := -1; // No index found
MinScore := CheckScore; // Lowest score so far
for i := Low(Scores) to High(Scores) do
if Scores[i].Score < MinScore then // Lower than CheckScore?
begin
MinScore := Scores[i].Score; // Yep. Store it (new lowest)
Result := i; // and where it was found
end;
end;
// Utility procedure to display list of scores
procedure PrintScores(const Prelude: string; Scores: TRecentScores);
var
Score: TRecentScore;
begin
WriteLn(Prelude);
for Score in Scores do
Writeln(' ' + Score.Name + ' = ' + IntToStr(Score.Score));
end;
var
RecentScores: TRecentScores;
CurrentScore: TRecentScore;
i: Integer;
begin
SetLength(RecentScores, 3);
RecentScores[0].Name := 'Tim';
RecentScores[0].Score := 14;
RecentScores[1].Name := 'Susan';
RecentScores[1].Score := 7;
RecentScores[2].Name := 'Derek';
RecentScores[2].Score := 12;
// Show scores where we begin
PrintScores('Before', RecentScores);
CurrentScore.Name := 'Gemma'; CurrentScore.Score := 9;
// Check for lower score than Gemma's
i := FindLowerScore(RecentScores, CurrentScore.Score);
if i = -1 then
WriteLn('No lower score found!')
else
begin
// We have a lower score in the array. Update that one
// with our new score.
RecentScores[i].Name := CurrentScore.Name;
RecentScores[i].Score := CurrentScore.Score;
PrintScores('After', RecentScores);
end;
ReadLn;
end.
Here is what i used, following your advice...
Procedure UpdateRecentScores(Var RecentScores : TRecentScores; Score : Integer);
Var
PlayerName : String;
Count : Integer;
FoundSpace : Boolean;
Begin
PlayerName := GetPlayerName;
FoundSpace := False;
Count := 1;
While Not FoundSpace And (Count <= NoOfRecentScores)
Do If RecentScores[Count].Name = ''
Then
begin
FoundSpace := True;
RecentScores[Count].Name := PlayerName;
RecentScores[Count].Score := Score;
end
Else Count := Count + 1;
If Not FoundSpace
Then
Begin
SortRecentScores(RecentScores); // sort them into order of score
if score > RecentScores[NoOfRecentScores].Score then
begin
RecentScores[NoOfRecentScores].Name:= PlayerName;
RecentScores[NoOfRecentScores].Score:= Score;
end;
End;
End;
I have a project where the program must accept 10 words and display the words in descending order (alphabetical order from Z-A)
using bubble sorting.
Here's what I know so far:
Program sample;
uses crt;
TYPE
no._list=ARRAY(1...10)OF REAL;
CONST
no.:no._list=(20.00,50.50.35.70....);
VAR
x:INTEGER;
small:REAL;
BEGIN clrscr:
small:=no.(1);
FOR x:=2 TO 10 DO
IF small>number(x);
writeln('Smallest value in the array of no.s is',small:7:2);
END
I really don't know how to do this though and could use some help.
Here's a video by Alister Christie on Bubble sort describing the principle :
http://codegearguru.com/index.php?option=com_content&task=view&id=64&Itemid=1
The algorithm in Pascal can be found # http://delphi.wikia.com/wiki/Bubble_sort
function BubbleSort( list: TStringList ): TStringList;
var
i, j: Integer;
temp: string;
begin
// bubble sort
for i := 0 to list.Count - 1 do begin
for j := 0 to ( list.Count - 1 ) - i do begin
// Condition to handle i=0 & j = 9. j+1 tries to access x[10] which
// is not there in zero based array
if ( j + 1 = list.Count ) then
continue;
if ( list.Strings[j] > list.Strings[j+1] ) then begin
temp := list.Strings[j];
list.Strings[j] := list.Strings[j+1];
list.Strings[j+1] := temp;
end; // endif
end; // endwhile
end; // endwhile
Result := list;
end;
I'm posting this in the spirit of answering your own questions.
The question I had was: How can I implement the Levenshtein algorithm for calculating edit-distance between two strings, as described here, in Delphi?
Just a note on performance:
This thing is very fast. On my desktop (2.33 Ghz dual-core, 2GB ram, WinXP), I can run through an array of 100K strings in less than one second.
function EditDistance(s, t: string): integer;
var
d : array of array of integer;
i,j,cost : integer;
begin
{
Compute the edit-distance between two strings.
Algorithm and description may be found at either of these two links:
http://en.wikipedia.org/wiki/Levenshtein_distance
http://www.google.com/search?q=Levenshtein+distance
}
//initialize our cost array
SetLength(d,Length(s)+1);
for i := Low(d) to High(d) do begin
SetLength(d[i],Length(t)+1);
end;
for i := Low(d) to High(d) do begin
d[i,0] := i;
for j := Low(d[i]) to High(d[i]) do begin
d[0,j] := j;
end;
end;
//store our costs in a 2-d grid
for i := Low(d)+1 to High(d) do begin
for j := Low(d[i])+1 to High(d[i]) do begin
if s[i] = t[j] then begin
cost := 0;
end
else begin
cost := 1;
end;
//to use "Min", add "Math" to your uses clause!
d[i,j] := Min(Min(
d[i-1,j]+1, //deletion
d[i,j-1]+1), //insertion
d[i-1,j-1]+cost //substitution
);
end; //for j
end; //for i
//now that we've stored the costs, return the final one
Result := d[Length(s),Length(t)];
//dynamic arrays are reference counted.
//no need to deallocate them
end;