String basic character Sequence container

The C language provides a specialized string type every day, and a character array is required to store and manipulate strings. In standard C + + , the string class is implemented by C + + STL . string is a character-based sequence container with an internal linear structure like vector vectors, with characters written to the container one after the other, ending with a null character. string provides a rich array of functions for adding, deleting, replacing, finding, and comparing characters, compared to traditional char* character arrays.

Create a String Object

There are several main ways to do this.

(1) string ()

string S;

(2) string (conststring&s,size_type pos=0,size_type n=npos)

string S1;

String S2 (S1);

(3) string (const char*)

char* carray= "ABC";

string s (cArray);

The addition of characters

The addition of characters is mainly push_back,append,insert and other functions.

#include <iostream> #include <string>using namespace Std;int main () {string S1;s1.push_back (' a '); s1.push_ Back (' B '); S1.push_back (' C '); cout<<s1<<endl;char* carray= "efgh"; string s2 (CArray);cout<<s2< <endl;cout<<s1+s2<<endl;cout<<s1.append (S2) <<endl; String::iterator I;i=s1.begin (); I++;s1.insert (i, ' 8 ');cout<<s1<<endl;s1+=s2;cout<<s1<< Endl;return 0;}

Traversal of characters

You can access the characters in a string using array mode and iterators [ support reverse iterator ] two ways.

#include <iostream> #include <string>using namespace Std;int main () {char* carray= "Hello,world"; string s ( CArray);//array mode for (int i=0;i<s.size (); i++) {Cout<<s[i]<<endl;} Iterator mode String::reverse_iterator rbegin,rend;rend=s.rend (); for (Rbegin=s.rbegin (); rbegin!=rend;rbegin++) {cout< <*rbegin<<endl;} return 0;}

Deletion of characters

Use the erase function and the clear function to implement the deletion of characters.

#include <iostream> #include <string>using namespace Std;int main () {char* carray= "a1234567"; string s ( CArray); S.erase (S.begin ()); Cout<<s<<endl;//1234567s.erase (S.begin () +2,s.end ()-2);cout<<s< <endl;//1267s.erase (0,2); Cout<<s<<endl;//67s.clear (); cout<<s<<endl;//return 0;}

Substitution of characters

Use the Replace function to implement the substitution of characters.

#include <iostream> #include <string>using namespace Std;int main () {char* carray= "hello,boy!"; string s (cArray); S.replace (6,3, "Girl"); Cout<<s<<endl;//hello,girl!s.replace (10,1,1, '. '); Cout<<s<<endl;//hello,girl.s.replace (S.begin (), S.begin () +5, "Good Morning");cout<<s<< Endl;//good Morning,girl.return 0;}

Search for characters

Use find,rfind,find_first_of,find_first_not_of,find_last_of, Find_last_not_of functions can implement character search, return the position of the string, not found, return -1.

#include <iostream> #include <string>using namespace Std;int main () {string S ("Dog bird Chicken Bird Cat");// String Lookup Cout<<s.find ("Bird") <<endl;//print 4cout<< (int) s.find ("Fish") <<endl;//-1//character lookup cout <<s.find (' I ', 0) <<endl;//5//finds the string Cout<<s.rfind ("Bird") from the end of the string <<endl;//17// Find the character cout<<s.rfind (' I ') starting at the end of the string <<endl;//18//find the first character that belongs to a substring cout<<s.find_first_of ("33r97") < <ENDL;//6//finds the first character that does not belong to a string cout<<s.find_first_not_of ("Dog Bird") <<endl;//9//finds the last character belonging to a substring cout <<s.find_last_of ("R") <<endl;//19//find the last character that does not belong to a string cout<<s.find_last_not_of ("Tea") << Endl;//22return 0;}

Comparison of strings

Use the compare function to achieve comparisons.

#include <iostream> #include <string>using namespace Std;int main () {string S1 ("ABCdef"); string s2 ("abc"); Cout<<s1.compare ("abcdef") <<endl;//equal, return 0cout<<s1.compare (S2) <<ENDL;//S1>S2, return positive Cout<<s1.compare ("Aby") <<endl;//s1< "Aby", Return-1 Cout<<s1.compare (0,3,S2) <<endl;// The first 3 characters of the S1 equals S2, returning 0 return 0;

Other common functions

There are other functions that give statistics about the string container, such as length,size,empty,c_str , and so on.

Here are just some of the functions, there are quite a number of functions are not listed, specifically can refer to the C + + Reference This site,http://www.cplusplus.com/reference/string/string/ , the site lists a variety of uses in detail.

#include <iostream> #include <string>using namespace Std;int main () {string S;cout<<s.empty () < <endl;//empty string, return 1s+= "1234567"; Cout<<s.empty () <<endl;//0cout<<s.length () <<endl;//7cout <<s.size () <<endl;//7const char* carray=s.c_str ();//Convert a string object to a character array Cout<<carray[2]<<endl ;//3 return 0;}

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String basic character Sequence container