Definition and function of the string of data structure Foundation

The definition of a string

A string (or string) that is a finite sequence of 0 or more characters. Generally recorded as:

S= ' a1a2...an ' (n>=0)

where S is the name of the string, the sequence of characters enclosed in single quotes is the value of the string, and the number of characters in the string n is called the length of the string. A string of 0 characters is called an empty string, and its length is zero.

A substring of any contiguous character in a string is called a substring of that string. The string containing the substring is referred to as the main string accordingly. The position of a character in a sequence, usually called the character in a string. The position of the substring in the main string is represented by the position of the first character of the substring in the main string.

Example: A= ' BEI ', b= ' JING ', c= ' BEIJING ', d= ' BEI JING '

The string length is 3,4,7,8, and the a,b is a c,d substring.

The two strings are called equal if and only if the values of the two strings are equal.

　　Second, the definition of the abstract data type of the string:

ADT string{

Data Objects: D={ai|ai (-characterset,i=1,2,..., n,n>=0}

Data relationship: R1={|ai-1,ai (-d,i=2,..., N}

Basic operations:

Strassign (&t,chars)

Chars is the constants quantity of words. Generates a string t whose value is equal to chars.

Strcopy (&t,s)

string s existence is copied by string s t

Strempty (S)

String s exists if s is empty string, return true otherwise return false

Strcompare (s,t)

string s and T exist, if s>t, the return value is greater than 0, if s=t, then the return value = 0, if s

Strlength (S)

The number of elements in a string s that returns s is called the length of the string.

Clearstring (&s)

String s exists to clear s to empty string

Concat (&T,S1,S2)

String S1 and S2 exist with T return a new string joined by S1 and S2

SubString (&sub,s,pos,len)

string s exist, 1<=pos<=strlength (s) and 0<=len<=strlength (s)-pos+1

Index (S,t,pos)

string s and T exist, T is Non-null, 1<=pos<=strlength (s), if there is a substring in the main string s that is the same as the string T value, it returns the position of the first occurrence after the POS character in the main string s, otherwise the function value is 0

Replace (&S,T,V)

The string s,t and V exist, T is a non-empty string, and with V replaces all occurrences of the not overlapping substrings in the main string s that are equal to T

Strinsert (&s,pos,t)

The string s and T exist, 1<=pos<=strlength (s) +1, before the first POS characters of the string s are inserted into the string t

Strdelete (&s,pos,len)

String S exists, 1<=pos<=strlength (s)-len+1 deletes the first POS characters from the string to the substring of Len

Destroystring (&s)

string s exist, then the string s are destroyed

}adt String

　　Three, series operation application Example:

1 commonly used in word processing: string lookup (comparison, positioning) and replacement

Available ^QF Quick Find variable in TC integrated environment can search and replace bulk change text in Word

2-string truncation and connection

Word processing can be done using substring and string connections

　Iv. Summary

Find a few examples of string operations that you've done yourself.