Standard Template Library

C + + study notes VI

The Standard Template Library is part of the C + + standard library and is a frequently used template in C + + programming. The common structure of this is described below. Mainly take string,vector,map,list as an example.

1.vector

General usage: #include <vector>

using namespace Std;

Vector<int > arr;

Common functions:

Push_back ()//Tail add

Pop_back ();//Tail Delete

Clear ();//Delete all elements

Vector: Dynamically increases memory,

arr.at (1) =1;<=>arr[1]=1;

Using iterators:

Vector<int>:;iterator ITER;

For (Iter=arr.begin (); Iter!=arr.end (); iter++) {

int &value =*iter;

printf ("%d\t", Arr[i]);

}

Vector is not suitable for inserting delete operations

2.list templates (linked list)

Push_back,pop_back

Push_front,pop_front

#include <list>

using namespace Std;

List does not support random access

List is more suitable for insert operations than vectors.

Importance: Vector is dispensable and list is indispensable

Class object{

};

List<object> Ls;//ls Object

Ls.push_back (Object (1, "Zhang San"));

Ls.push_back (Object (2, "John Doe"));

To define an iterator:

List<object>::iterator iter;//iterator is a pointer type

For (Iter=ls.begin (); Iter!=ls.end (); iter++) {

Object &value=*iter;

printf ("%d,%s", value.id,value.name);

}

Delete

For (Iter=ls.begin (); Iter!=ls.end (); iter++) {

Object &value=*iter;

if (value.id=3) {

Ls.erase (ITER);

Break

}

}

Customizing the list template is a hassle, and it's more convenient to use the lists template.

3.string templates

Common functions: Append,clear,capacity,size,lengeh,at,find

#include <string>

using namespace Std;

String str1;//represents an empty string.

String str2 ("Abcde ', 5);

Note: cannot initialize to null

1) Adding elements

Str1.append ("Abscd ', 3);//Copy length 3;

Str1.append ("Abdcde", 1, 3);//subscript 1 to Subscript 3

Str1.append (4, ' h ');//Added 4 H characters.

Access string content: str1.at (i) =j;<==>str1[i]=j;

2) comparison

Relational operators such as ==,>= can be used directly because they are overloaded.

3) Find and extract substrings

Find (' i ');//finds the position of I and returns

RFind (' i ');//start looking for the right

T1.SUBSTR (4);//starting from the fourth character to take an element

T1.SUBSTR (4,3)//starting from fourth, length is 3;

4) string is a template type, which is passed as a function parameter, using a reference

void Test (const string &t) {}//does not change memory value

void Test (String &t) {}//Changes memory value

5) String class member function c_str ();

Returns a C-style string that is the same as the String class object itself; Converts a string object into a string format in C by using the C_STR () function in the String class.

String S1 ("abc");

printf ('%s\n ', S1.c_str ());

Example: const char *p=s1.c_str ();

printf ("%s\n", p);

6) Access to strings:

At or [] to access

String can be used directly in the standard Template Library, unlike other types.

Add: The reference must be initialized, and the pointer will be

Standard Template Library