![Lecture 01: DS & Algorithms:2013
Iftikhar
Traversal
• Traversing:
• In traversing operation, each element of an array is accessed
exactly once for processing. This is called visiting of the array.
• To compute the sum of values of each element of an array.
• Display values of each element of an array.
• Algorithm:
• 1. Set k=LB
• 2. Repeat Step 3 and Step 4 while k<=UB
• 3. Apply PROCESS to LA[K]
• 4. Set K=K+1
• 5. [End of Step 2 loop]
• 6. Exit
3](https://image.slidesharecdn.com/arrayoperations-141027060649-conversion-gate02/85/Array-operations-3-320.jpg)
![Lecture 01: DS & Algorithms:2013
Iftikhar
Traversal Algo
• Find the Number NUM of years during which
more than 300 automobiles were sold.
• 1. Set NUM=0
• 2. Repeat for K=1932 to 1984
• 3. If AUTO[K]>300, then: Set NUM=NUM +1.
• 4. [End of Loop]
• 5. Return
4](https://image.slidesharecdn.com/arrayoperations-141027060649-conversion-gate02/85/Array-operations-4-320.jpg)
![Lecture 01: DS & Algorithms:2013
Iftikhar
Inserting
• Algorithm- Inserting value at specified location
1. Set J=N
2. Repeat Step 3 and Step 4 while J>=K
3. Set LA[J+1]=LA[J]
4. Set J=J-1
5. [End of Step 2 loop]
6. Set LA[K]=ITEM
7. Set N=N+1
8. Exit
6](https://image.slidesharecdn.com/arrayoperations-141027060649-conversion-gate02/85/Array-operations-6-320.jpg)
![Lecture 01: DS & Algorithms:2013
Iftikhar
Deletion
• Deleting item from a specified Location
• When the data item is removed from a specified location within an
array, the items from that location up to the end of array are moved
one location towards the beginning of the array.
• Algorithm:
1. Set ITEM=LA[K]
2. Repeat for J=K to N-1
3. Set LA[J]=LA[J+1]
4. [End of loop]
5. Set N=N-1
6. Exit
7](https://image.slidesharecdn.com/arrayoperations-141027060649-conversion-gate02/85/Array-operations-7-320.jpg)
![Lecture 01: DS & Algorithms:2013
Iftikhar
Search
• The sequential search is a slow process and is used for only small lists of data.
• The Method is not recommended for large amount of data because some more
efficient methods are available for large and complex searches.
• Algorithm: Linear Search
1. SET LOC=-1
2. INPUT N values into array XYZ
3. INPUT VAL
4. Repeat Step 5 For I= 1 TO N
5. IF VAL = XYZ[I] THEN
6. LOC=1
7. Print “value found at location”, LOC
8. Exit
9. END IF
10. If LOC=-1 THEN
11. PRINT ”Value is not Found”
12. END IF
13. EXIT
9](https://image.slidesharecdn.com/arrayoperations-141027060649-conversion-gate02/85/Array-operations-9-320.jpg)
![Lecture 01: DS & Algorithms:2013
Iftikhar
Search(Binary Search)
1. Set BEG=LB, END=UB and MID=INT((BEG+ENG)/2
2. Repeat Steps 3 and 9 while BEB<=ENG and DATA[MID]!=ITEM
3. If ITEM<DATA[MID],then
4. Set END=MID-1
5. Else
6. Set BEG=MID+1
7. END IF
8. Set MID=INT((BEG+END))/2
9. END OF LOOP
10. If DATA[MID]=ITEM, then
11. Set LOC=MID
12. Else
13. Set LOC=NULL
14. END IF
15. EXIT
10](https://image.slidesharecdn.com/arrayoperations-141027060649-conversion-gate02/85/Array-operations-10-320.jpg)
Array operations
- 1. Lecture 01: DS & Algorithms:2013 DATA STRUCTURES & ALGORITHMS Iftikhar Muhammad 1 Iftikhar 1
- 2. Lecture 01: DS & Algorithms:2013 Iftikhar Arrays Operations • Traversal • Inserting • Deletion • Search • Sorting 2
- 3. Lecture 01: DS & Algorithms:2013 Iftikhar Traversal • Traversing: • In traversing operation, each element of an array is accessed exactly once for processing. This is called visiting of the array. • To compute the sum of values of each element of an array. • Display values of each element of an array. • Algorithm: • 1. Set k=LB • 2. Repeat Step 3 and Step 4 while k<=UB • 3. Apply PROCESS to LA[K] • 4. Set K=K+1 • 5. [End of Step 2 loop] • 6. Exit 3
- 4. Lecture 01: DS & Algorithms:2013 Iftikhar Traversal Algo • Find the Number NUM of years during which more than 300 automobiles were sold. • 1. Set NUM=0 • 2. Repeat for K=1932 to 1984 • 3. If AUTO[K]>300, then: Set NUM=NUM +1. • 4. [End of Loop] • 5. Return 4
- 5. Lecture 01: DS & Algorithms:2013 Iftikhar Inserting • In inserting operation , new data items are added or inserted into any location of an empty or filled array. • In case of empty array, new values are stored in empty locations. • In case of filled array , old values are either replaced by new values or pushed backward to make room for new values. • It is very easy to insert data at the end of array(Why?). • Without disturbing the data of other elements of the array. 5
- 6. Lecture 01: DS & Algorithms:2013 Iftikhar Inserting • Algorithm- Inserting value at specified location 1. Set J=N 2. Repeat Step 3 and Step 4 while J>=K 3. Set LA[J+1]=LA[J] 4. Set J=J-1 5. [End of Step 2 loop] 6. Set LA[K]=ITEM 7. Set N=N+1 8. Exit 6
- 7. Lecture 01: DS & Algorithms:2013 Iftikhar Deletion • Deleting item from a specified Location • When the data item is removed from a specified location within an array, the items from that location up to the end of array are moved one location towards the beginning of the array. • Algorithm: 1. Set ITEM=LA[K] 2. Repeat for J=K to N-1 3. Set LA[J]=LA[J+1] 4. [End of loop] 5. Set N=N-1 6. Exit 7
- 8. Lecture 01: DS & Algorithms:2013 Iftikhar Search • The Process of finding a specific data item and its location in an array is called searching. • Successful- If found • Terminated- If data item found • Unsuccessful • Searching Operation in data structures is used for data modification together with inserting, deleting and updating. • For example , when a data item is to be deleted , it is first searched and then deleted, if found. • The most commonly used search algorithms are as follows. • i. Sequential Search • Ii. Binary Search 8
- 9. Lecture 01: DS & Algorithms:2013 Iftikhar Search • The sequential search is a slow process and is used for only small lists of data. • The Method is not recommended for large amount of data because some more efficient methods are available for large and complex searches. • Algorithm: Linear Search 1. SET LOC=-1 2. INPUT N values into array XYZ 3. INPUT VAL 4. Repeat Step 5 For I= 1 TO N 5. IF VAL = XYZ[I] THEN 6. LOC=1 7. Print “value found at location”, LOC 8. Exit 9. END IF 10. If LOC=-1 THEN 11. PRINT ”Value is not Found” 12. END IF 13. EXIT 9
- 10. Lecture 01: DS & Algorithms:2013 Iftikhar Search(Binary Search) 1. Set BEG=LB, END=UB and MID=INT((BEG+ENG)/2 2. Repeat Steps 3 and 9 while BEB<=ENG and DATA[MID]!=ITEM 3. If ITEM<DATA[MID],then 4. Set END=MID-1 5. Else 6. Set BEG=MID+1 7. END IF 8. Set MID=INT((BEG+END))/2 9. END OF LOOP 10. If DATA[MID]=ITEM, then 11. Set LOC=MID 12. Else 13. Set LOC=NULL 14. END IF 15. EXIT 10