This is my course in Pascal PL in 2013

1. Prog_2 course- 2014
2 bytes team
Kinan keshkeh
IT Engineering-Damascus University
3rd year

2. Double Lists
Data
next
prev
L_S
Data
next
prev
Data
prev
prev
next
next
Data
L_E

3. Definition
Type
D_P = ^D_R;
D_R = Record
ID:integer;
next:D_P;
prev:D_P;
end;
var
L_S, L_E : D_P;

4. Double Lists Procedures:
1) Insert a Node
2) Delete a Node
3) Search Node

5. Insert a Node
Data
next
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Data
next
prev
Data
next
prev
Data
next
prev
L_E
Data
next
prev
L_S
Temp

6. 1)
L_S
Nil
15
next
prev
Temp
L_E

7. 3
next
prev
20
next
prev
15
next
prev
2)
L_S
S
L_E
Temp

8. 3
next
prev
20
next
prev
15
next
prev
3)
L_S
S
L_E
2
next
prev
Temp

9. 3
next
prev
20
next
prev
15
next
prev
L_S
S
L_E
2
next
prev
Nil
4)
Temp

10. procedure D_L_Insert ( var L_S, L_E: D_P; KEY:integer);
var
Temp , S : D_P;
Located: Boolean;
begin
new(Temp);
temp^.ID:=KEY;
temp^.next:=nil;
temp^.prev:=nil;
15
next
prev
Temp

11. If L_S=nil then
begin
L_S:=Temp;
L_E:=Temp;
end
Else
begin
S:=L_S;
Located:=False;
while (S<>nil) and (not Located) do
if S^.id < key then
S:=S^.next
else
Located:=True;
Temp^.next:=S;
+2 points

12. If S=L_S then
begin
L_S^.prev:=Temp;
L_S:=Temp;
end
Else if S=nil then
begin
Temp^.prev := L_E;
L_E^.next := Temp;
L_E:=Temp;
end
Else
begin
Temp^.prev := S^.prev;
S^.prev^.next := Temp;
S^.prev := Temp;
end;
end;
end; {procedure}

13. 1)
L_S
Nil
Delete a Node
flag
3
L_E

14. 3
next
prev
20
next
prev
15
next
prev
L_S
L_E
key
3
2)
temp
3
next
prev
L_S
Nil
temp
L_E
flag
2

15. 3
next
prev
20
next
prev
15
next
prev
L_S
L_E
temp
3)
falg
2
key
20

16. 3
next
prev
20
next
prev
15
next
prev
L_S
L_E
4)
flag
2
key
15
S

17. 3
next
prev
20
next
prev
15
next
prev
L_S
L_E
Nil
flag
1
key
99
5)
S

18. procedure D_L_Delete ( var L_S,L_E: D_P; KEY:integer; var flag :char);
var
Temp , S:D_P;
begin
If L_S=nil then
flag:=‘3’
Else if KEY =L_S^.id then
begin
Temp:=L_S;
L_S:=L_S^.next; ls^.prev:=nill ;
Dispose(Temp);
flag:=‘2’;
If L_s=nil then
L_E:=nil;
Else
L_s^.prev:=nil;
end

19. Else if KEY = L_E^.id then
begin
Temp:=L_E;
L_E:=L_E^.prev; L_E^.next:=nil; Dispose(Temp);
Flag:=‘2’;
end
Else
begin
S:=L_S;
while (S<>nil) and (S^.id <> KEY ) do
S:=S^.next;
if S=nil then
flag:=‘1’;
else
begin
S^.next^.prev:=S^.prev;
S^.prev^.next:=S^.next; Dispose(S);
flag:=‘ 2 ’;
end;
end;
end; {procedure}

20. Homework:
+15 points
اكتب اجرائية البحث عه عنصر ما في سلسة مترابطة
مه طرفيه :
Search( var L_s, L_E : D_P ; Key:integer;
var p: D_P ; var flag: char);
بحيث تحفظ الاجرائية مؤشر على مكان العنصر المراد,
وتعيد محرف يعبر عه حالة البحث ) فشل-وجد العنصر-
السلسلة فارغة(

21. Group : group link
Mobile phone- Kinan : 0994385748
Facebook account : kinan’s account
2 bytes team