2012年10月27日整理 郑海波
(一)list简介：
list不像vector那样，list的内存分配时非连续的，因此，只能通过迭代器来访问list中的元素。另外，list在头和尾都可以插入元素
(二)创建一个list1.首先包含list的头文件2.使用标准的std命名空间#include <list>usingnamespacestd;一下是构造list的不同方法：
[c++ code list1.cpp]
#pragma warning(disable:4786)
#include <iostream>
#include <list>
#include <string>
using namespace std;
class Student{
private:
int ID;
string Name;
public:
Student(int ID,string Name)
{
this->ID=ID;
this->Name=Name;
}
int getID()
{
return ID;
}
string getName()
{
return Name;
}
};
int main()
{
// create an empty list (of zero size) capable of holding doubles
list<double> list0;
cout << "Size of list0 is " << list0.size() << endl;
// create a list with 5 empty elements
list<double> list1(5);
cout << "Size of list1 is " << list1.size() << endl;
// create a list with 5 elements, each element having the value 10.2
list<double> list2(5, 10.2);
cout << "list2: ";
list<double>::iterator it;
for(it = list2.begin(); it != list2.end(); ++it)
cout << *it << " ";
cout << endl;
// create a list based on an array of elements
// only the first 5 elements of the array are copied into the vector
double array[8] = {3.45, 67, 10, 0.67, 8.99, 9.78, 6.77, 34.677};
list<double> list3(array, array + 5);
cout << "list3: ";
for(it = list3.begin(); it != list3.end(); ++it)
cout << *it << " ";
cout << endl;
// use the copy constructor to copy list3 list into list3copy list
list<double> list3copy(list3);
cout << "list3copy: ";
for(it = list3copy.begin(); it != list3copy.end(); ++it)
cout << *it << " ";
cout << endl;
// assign 5 values of 10.2 to the list
list<double> list4;
list4.assign(5, 10.2);
cout << "list4: ";
for(it = list4.begin(); it != list4.end(); ++it)
cout << *it << " ";
cout << endl;
//定义自己的数据类型
list<Student> list5;
Student stu1(1,"ZhengHaibo");
Student stu2(2,"nupt");
list5.push_back(stu1);
list5.push_back(stu2);
list<Student>::iterator iter_stu;
cout << "list5: "<<endl;
for (iter_stu=list5.begin();iter_stu!=list5.end();iter_stu++)
{
cout<<"ID:"<<iter_stu->getID()<<" Name:"<<iter_stu->getName()<<endl;
}
return 0;
// Output
// Size of list0 is 0
// Size of list1 is 5
// list2: 10.2 10.2 10.2 10.2 10.2
// list3: 3.45 67 10 0.67 8.99
// list3copy: 3.45 67 10 0.67 8.99
// list4: 10.2 10.2 10.2 10.2 10.2
//list5:
//ID:1 Name:ZhengHaibo
//ID:2 Name:nupt
}
(三)访问输出list中的值
在list中，由于其内存是非连续的，因此不能像vector那样，用[]操作符取值，只能用迭代器。
[c++ code list2.cpp]
#pragma warning(disable:4786)
#include <iostream>
#include <list>
#include <string>
using namespace std;
//Printing the elements of a list can only be done through iterators.
void print(list<double> lst, char * name)
{
list<double>::iterator it;
cout << name << ": ";
for(it = lst.begin(); it != lst.end(); ++it)
cout << *it << " ";
cout << endl;
}
int main()
{
double array[8] = {3.45, 67, 10, 0.67, 8.99, 9.78, 6.77, 34.677};
list<double> lst(array, array + 5);
print(lst, "lst");
cout << "lst in reverse order: ";
list<double>::reverse_iterator rit;//
for(rit = lst.rbegin(); rit != lst.rend(); ++rit)
cout << *rit << " ";
return 0;
//Output
// lst: 3.45 67 10 0.67 8.99
// lst in reverse order: 8.99 0.67 10 67 3.45
}
(四)向list中插入元素
与vector相比，list除了有push_back()//在尾部插入 和 insert()之外，还有push_front()//即在链表的头部插入
[c++ code list3.cpp]
#pragma warning(disable:4786)
#include <iostream>
#include <list>
#include <string>
using namespace std;
//Printing the elements of a list can only be done through iterators.
void print(list<double> lst, char * name)
{
list<double>::iterator it;
cout << name << ": ";
for(it = lst.begin(); it != lst.end(); ++it)
cout << *it << " ";
cout << endl;
}
int main()
{
list<double> lst;
list<double>::iterator it;
// add elements to the end of the list
lst.push_back(2.4);
lst.push_back(4.5);
lst.push_back(0.98);
print(lst, "lst");
// insert value 6.7 in the second position in the list
it = lst.begin();
lst.insert(++it, 6.7);
print(lst, "lst");
// insert elements from the array at the end of the list
double array[2] = {100.89, 789.76};
it = lst.end();
lst.insert(it, array, array + 2);
print(lst, "lst");
// add elements to the beginning of the list
lst.push_front(0.45);
lst.push_front(0.56);
lst.push_front(0.78);
print(lst, "lst");
return 0;
// Output
// lst: 2.4 4.5 0.98
// lst: 2.4 6.7 4.5 0.98
// lst: 2.4 6.7 4.5 0.98 100.89 789.76
// lst: 0.78 0.56 0.45 2.4 6.7 4.5 0.98 100.89 789.76
}
(五)删除list中的元素
主要有如下函数：pop_back(),pop_front(),erase(),remove(),remove_if(),unique(),clear()<empty()>;
与插入元素相对应，list用pop_back()//在尾部删除一个元素,pop_front()//在头部删除一个元素,erase()删除任意部位
[c++ code list4.cpp]
#pragma warning(disable:4786)
#include <iostream>
#include <list>
#include <string>
using namespace std;
//Printing the elements of a list can only be done through iterators.
void print(list<double> lst, char * name)
{
list<double>::iterator it;
cout << name << ": ";
for(it = lst.begin(); it != lst.end(); ++it)
cout << *it << " ";
cout << endl;
}
int main()
{
double array[10] = {3.45, 67, 10, 0.67, 8.99, 9.78, 6.77, 34.677, 100.67, 0.99};
list<double> lst(array, array + 10);
list<double>::iterator it;
print(lst, "lst");
// remove the last element of the list
lst.pop_back();
print(lst, "lst");
// remove the second element of the list
it = lst.begin();
lst.erase(++it);
print(lst, "lst");
// remove the first element of the list
lst.pop_front();
print(lst, "lst");
return 0;
// Output
// lst: 3.45 67 10 0.67 8.99 9.78 6.77 34.677 100.67 0.99
// lst: 3.45 67 10 0.67 8.99 9.78 6.77 34.677 100.67
// lst: 3.45 10 0.67 8.99 9.78 6.77 34.677 100.67
// lst: 10 0.67 8.99 9.78 6.77 34.677 100.67
}
另外，list还有remove()函数，remove()函数也是删除一个元素，但是，它的参数是元素的值或者是对象，而不是迭代器.同时，还有remove_if()函数,该函数的参数是一个函数，是一个返回值为bool，参数为元素类型的一个函数。
[c++ code list5.cpp]//注意：该程序在VC6.0下编译报错，建议使用g++或gcc。
#pragma warning(disable:4786)
#include <iostream>
#include <list>
#include <string>
using namespace std;
//Printing the elements of a list can only be done through iterators.
void print(list<double> lst, char * name)
{
list<double>::iterator it;
cout << name << ": ";
for(it = lst.begin(); it != lst.end(); ++it)
cout << *it << " ";
cout << endl;
}
bool zhb_predicate(double& element)
{
return (element >= 15.0) ? true : false;
}
int main()
{
double array[10] = {3.45, 67, 19.25, 0.67, 8.99, 9.78, 19.25, 34.677, 100.67, 19.25};
list<double> lst(array, array + 10);
print(lst, "lst");
// remove all elements with value 19.25 from the list
lst.remove(19.25);
print(lst, "lst");
lst.remove_if(zhb_predicate);
print(lst, "lst");
return 0;
//lst: 3.45 67 19.25 0.67 8.99 9.78 19.25 34.677 100.67 19.25
//lst: 3.45 67 0.67 8.99 9.78 34.677 100.67
//lst: 3.45 0.67 8.99 9.78
}
另外一个删除元素的函数式unique()函数，还函数有2中调用方式。无参数调用的情况下，如果该元素与其前一个元素相同，则删除之。当然，我们也可以传递一个判断是否相等的一个函数。
[c++ code list6.cpp]//注意：该程序在VC6.0下编译报错，建议使用g++或gcc
#pragma warning(disable:4786)
#include <iostream>
#include <list>
#include <cmath>
#include <string>
using namespace std;
//Printing the elements of a list can only be done through iterators.
void print(list<double> lst, char * name)
{
list<double>::iterator it;
cout << name << ": ";
for(it = lst.begin(); it != lst.end(); ++it)
cout << *it << " ";
cout << endl;
}
bool almost_equal(double& el1, double& el2)
{
return (fabs(el1 - el2) <= 0.1) ? true : false;
}
int main()
{
double array[10] = {3.45, 0.67, 0.67, 0.62, 8.99, 8.98, 8.99, 34.677, 100.67, 19.25};
list<double> lst(array, array + 10);
print(lst, "lst");
// remove all duplicate elements from the list
lst.unique();
print(lst, "lst");
// remove all duplicate elements from the list
lst.unique(almost_equal);
print(lst, "lst");
return 0;
//Output
// lst: 3.45 0.67 0.67 0.62 8.99 8.98 8.99 34.677 100.67 19.25
// lst: 3.45 0.67 0.62 8.99 8.98 8.99 34.677 100.67 19.25
// lst: 3.45 0.67 8.99 34.677 100.67 19.25
}
(六)链表的长度及重置链表的长度
与vector不同的是，list没有capacity() 和 reserve()函数。list用size获得链表的长度，用resize改变其大小。
[c++ code list7.cpp]
#pragma warning(disable:4786)
#include <iostream>
#include <list>
#include <cmath>
#include <string>
using namespace std;
//Printing the elements of a list can only be done through iterators.
void print(list<double> lst, char * name)
{
list<double>::iterator it;
cout << name << ": ";
for(it = lst.begin(); it != lst.end(); ++it)
cout << *it << " ";
cout << endl;
}
int main()
{
list<double> lst;
lst.push_back(0.67);
lst.push_back(7.89);
lst.push_back(3.56);
lst.push_back(10.67);
lst.push_back(9.89);
cout << "lst size is " << lst.size() << endl;
print(lst, "lst");
// case when new size <= size of list
lst.resize(3);
cout << "lst size is " << lst.size() << endl;
print(lst, "lst");
// case when new size > size of list
lst.resize(10);
cout << "lst size is " << lst.size() << endl;
print(lst, "lst");
return 0;
// Output
// lst size is 5
// lst: 0.67 7.89 3.56 10.67 9.89
// lst size is 3
// lst: 0.67 7.89 3.56
// lst size is 10
// lst: 0.67 7.89 3.56 0 0 0 0 0 0 0
}
(七)反转一个链表
调用reverse()函数即可，很简单，不再举例。
(八)链表元素的排序
用sort()函数进行排序，默认情况下是从小到大，当然，也可以人为地改变。
[c++ code list8.cpp]//注意：该程序在VC6.0下编译报错，建议使用g++或gcc
#pragma warning(disable:4786)
#include <iostream>
#include <list>
#include <cmath>
#include <string>
using namespace std;
//Printing the elements of a list can only be done through iterators.
void print(list<double> lst, char * name)
{
list<double>::iterator it;
cout << name << ": ";
for(it = lst.begin(); it != lst.end(); ++it)
cout << *it << " ";
cout << endl;
}
int main()
{
double array[10] = {3.45, 3.455, 67, 0.67, 8.99, 9.0, 9.01, 34.677, 100.67, 19.25};
list<double> lst(array, array + 10);
print(lst, "lst");
// sort the list;
// < operator will be used as default
// the elements will be sorted in ascending order
lst.sort();
print(lst, "lst in ascending order");
// sort the list; specify the sorting function
// > operator will be used in this case
// the elements will be sorted in descending order
lst.sort( greater<double>() );
print(lst, "lst in descending order");
// sort the list; specify the sorting function
// < operator will be used in this case
// the elements will be sorted in descending order
lst.sort( less<double>() );
print(lst, "lst in ascending order");
return 0;
// Output
// lst: 3.45 3.455 67 0.67 8.99 9 9.01 34.677 100.67 19.25
// lst in ascending order: 0.67 3.45 3.455 8.99 9 9.01 19.25 34.677 67 100.67
// lst in descending order: 100.67 67 34.677 19.25 9.01 9 8.99 3.455 3.45 0.67
// lst in ascending order: 0.67 3.45 3.455 8.99 9 9.01 19.25 34.677 67 100.67
}
(九)交换两个链表
直接调用swap()函数即可。
lst1.swap(lst2);
(十)合并两个链表
主要有两个函数：splice()和merge()
splice()有三种调用形式：
第一种： list1.splice(it1, list2).将list2中的所有元素拷贝到list1中。在list1中的起始位置是it1.复制结束后，list2将为空。
[c++ code]
list<double> list1;
list<double> list2;
list1.push_back(1.0);
list1.push_back(5.0);
list1.push_back(6.0);
list1.push_back(7.0);
list1.push_back(8.0);
list2.push_back(2.0);
list2.push_back(3.0);
list2.push_back(4.0);
cout << "Before splice: " << endl;
print(list1, "list1");
print(list2, "list2");
list<double>::iterator it1 = list1.begin();
++it1;
// move all the elements of list2 into list1,
// starting from the second position
list1.splice(it1, list2);
cout << "After splice: " << endl;
print(list1, "list1");
print(list2, "list2");
// Output
// Before splice:
// list1: 1 5 6 7 8
// list2: 2 3 4
// After splice:
// list1: 1 2 3 4 5 6 7 8
// list2:
第二种调用形式：
list1.splice(it1, list2, it2)
这个功能是将list2中的元素，从it2开始，剪切到list1的it1起始的地方。
第三种调用形式：
list1.splice(it1, list2, it2begin, it2end)
merge函数的使用：
形式：list1.merge(list2)
注意：在使用merge之前，必须使list1和list2已经排好顺序。并且，合并之后list1仍然是有序的。
list<double> list1;
list<double> list2;
list1.push_back(1.0);
list1.push_back(5.0);
list1.push_back(6.0);
list1.push_back(7.0);
list1.push_back(8.0);
list2.push_back(2.0);
list2.push_back(3.0);
list2.push_back(4.0);
cout << "Beforemerge: " <<endl;
print(list1, "list1");
print(list2, "list2");
// merge the two lists
list1.merge(list2);
cout << "Aftermerge: " <<endl;
print(list1, "list1");
print(list2, "list2");
// Output
// Before merge:
// list1: 1 5 6 7 8
// list2: 2 3 4
// After merge:
// list1: 1 2 3 4 5 6 7 8
// list2:
(十一)二维链表
所谓二维链表就是链表的链表。
list< list<double> > matrix;
list<double> lst1(5, 6.713);
list<double> lst2(6, 5.678);
matrix.push_back(lst1);
matrix.push_back(lst2);
list< list<double> >::iterator it2d;
for(it2d = matrix.begin(); it2d != matrix.end(); it2d++)
print(*it2d, "row");
// Output
// row: 6.713 6.713 6.713 6.713 6.713
// row: 5.678 5.678 5.678 5.678 5.678 5.678
(十二)用户自定义的元素类型
为了能够使用stl中的算法，用户自定义的类必须实现很多运算符的重载。g++编译通过
#pragma warning(disable:4786)
#include <iostream>
#include <list>
#include <cmath>
#include <string.h>
using namespace std;
class Person
{
char * name;
char sex;
int age;
public:
// constructor
Person()
{
name = new char[strlen("Anonymous") + 1];
sex = 'N';
age = 0;
}
// constructor
Person(char * pName, char pSex, int pAge)
: sex(pSex), age(pAge)
{
name = new char[strlen(pName) + 1];
strcpy(name, pName);
}
// copy constructor
Person(const Person& rhs)
: sex(rhs.sex), age(rhs.age)
{
name = new char[strlen(rhs.name) + 1];
strcpy(name, rhs.name);
}
// overload the assignment operator
Person& operator=(const Person& rhs)
{
name = new char[strlen(rhs.name) + 1];
strcpy(name, rhs.name);
sex = rhs.sex;
age = rhs.age;
return *this;
}
// overload the == operator
// for sorting purposes, we consider that two Person objects are "equal"
// if they have the same age
bool operator==(const Person& rhs) const
{
return (age == rhs.age) ? true : false;
}
// overload the < operator
// for sorting purposes, we consider that a Person object is "less than" another
// if it's age is less than the other object's age
bool operator<(const Person& rhs) const
{
return (age < rhs.age) ? true : false;
}
// overload the > operator
// for sorting purposes, we consider that a Person object is "greater than" another
// if it's age is greater than the other object's age
bool operator>(const Person& rhs) const
{
return (age > rhs.age) ? true : false;
}
// print the object
void print()
{
cout << name << " " << sex << " " << age << endl;
}
// destructor
~Person()
{
delete []name;
}
};
void print(list<Person> lst, char * name)
{
list<Person>::iterator it;
cout << name << ":" << endl;
for(it = lst.begin(); it != lst.end(); ++it)
it->print();
cout << endl;
}
int main()
{
list<Person> lst;
// create some Person objects
Person p1("Bill Gates", 'M', 50);
Person p2("Scott Meyers", 'M', 43);
Person p3("Charles Petzold", 'M', 48);
Person p4("Christina Dermayr", 'F', 30);
Person p5("Andrei Neagu", 'M', 22);
Person p6("Yin Su", 'F', 56);
Person p7("Georgeta Bills", 'F', 37);
// add the objects to the list
lst.push_back(p1);
lst.push_back(p2);
lst.push_back(p3);
lst.push_back(p4);
lst.push_back(p5);
lst.push_front(p6);
lst.push_front(p7);
print(lst, "lst");
// sort the list in ascending order
lst.sort( less<Person>() );
print(lst, "lst in ascending order");
// sort the list in descending order
lst.sort( greater<Person>() );
print(lst, "lst in descending order");
// delete the first element from the list
lst.pop_front();
print(lst, "lst");
// clear the list
lst.clear();
if(lst.empty())
cout << "lst is empty" << endl;
else
cout << "lst is not empty" << endl;
return 0;
// Output
// lst:
// Georgeta Bills F 37
//Yin Su F 56
// Bill Gates M 50
// Scott Meyers M 43
// Charles Petzold M 48
// Christina Dermayr F 30
// Andrei Neagu M 22
//
// lst in ascending order:
// Andrei Neagu M 22
// Christina Dermayr F 30
// Georgeta Bills F 37
// Scott Meyers M 43
// Charles Petzold M 48
// Bill Gates M 50
// Yin Su F 56
//
// lst in descending order:
// Yin Su F 56
// Bill Gates M 50
// Charles Petzold M 48
// Scott Meyers M 43
// Georgeta Bills F 37
// Christina Dermayr F 30
// Andrei Neagu M 22
//
// lst:
// Bill Gates M 50
// Charles Petzold M 48
// Scott Meyers M 43
// Georgeta Bills F 37
// Christina Dermayr F 30
// Andrei Neagu M 22
//
// lst is empty
}
参考：http://www.codeproject.com/Articles/20960/The-complete-guide-to-STL-Part-2-List
