Data structure and Algorithm course material, CSC-391.

1. String Operation
Csc-391

2. 2
Data Structures and Algorithms
Remarks
• Each programming language contains a character
set that is used to communicate with the
computer. This set usually includes the
followings-
• Alphabet- A B C D… X Y Z
• Digits- 0 1 2.. 9
• Special Characters- + - / * . (), {}, , $ etc..
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3. 3
Data Structures and Algorithms
Storing String
• For Example,
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4. 4
Data Structures and Algorithms
Storing String
• 1. Fixed- length storage.
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5. 5
Data Structures and Algorithms
Storing String
• 1. Fixed- length storage.
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6. 6
Data Structures and Algorithms
Storing String
• 2. Variable- length storage with fixed maximum.
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7. 7
Data Structures and Algorithms
Storing String
• 2. Variable- length storage with fixed maximum.
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8. 8
Data Structures and Algorithms
Storing String
• 3. Linked storage
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9. 9
Data Structures and Algorithms
String Operation
• Length: LENGTH (string)
e.g.- LENGTH(‘Mark Zuckerberg’)= 15
• Substring: SUBSTRING(string, initial, length)
e.g.- SUBSTRING(‘Impossible is a word found in coward’s dictionary’,0,20) =
Impossible is a word
• Indexing: INDEX(string, pattern)
e.g.- INDEX(‘He is wearing glasses’, ‘ear’)= 8
• Concatenation: String1//String2
e.g.- ‘To be or not to be’// ‘, this is the question.’= To be or not to be, this is the
question
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10. ©SMT, Faculty, CSE, IUBAT
String Operation
• Word Processing-
Insertion: INSERT(string, position, string)
e.g.- INSERT(‘ABCDEIJKL’,5,‘FGH’)=
ABCDEFGHIJKL
Deletion: DELETE(string, position, length)
e.g.- DELETE(‘ABCDEFG’, 4, 2)= ABCDG

11. 11
Data Structures and Algorithms
String Operation
– Replacement: REPLACE(string, pattern1, pattern2)
e.g.- REPLACE(‘XABYABZ’, ‘AB’, ‘c’)= XCYABZ
REPLACE function can be executed be using the following three steps-
1. K:= INDEX(string, P1)
2. T:= DELETE(string, K, LENGTH(P1))
3. INSERT(T, K, P1)
– So, the algorithm is-
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12. 12
Data Structures and Algorithms
String Operation
– Pattern Matching:
Pattern matching is the problem of deciding whether or not a given string pattern
P appears in a text.
Widely used in word processing.
– So, a basic algorithm is-
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