STL - 容器 - List

List内部结构完全不同于array, vector, deque。

它提供了两个pointer，指向第一个和最后一个元素。

不支持随机访问元素，因此要访问第n个元素必须爬过n - 1个元素。

在任何位置上执行元素的插入和删除操作都很快。

因此会有一些属于list的特殊类型操作，比如merge, splice等。

ListTest.cpp

#include <iostream>
#include <deque>
#include <list>
#include <iostream>
#include <algorithm>
#include <iterator>
#include "ListTest.h"

using namespace std;

void ListTest::printLists(const list<int>& l1, const list<int>& l2)
{
    cout << "list1: ";
    copy(l1.cbegin(), l1.cend(), ostream_iterator<int>(cout, " "));
    cout << endl << "list2: ";
    copy(l2.cbegin(), l2.cend(), ostream_iterator<int>(cout, " "));
    cout << endl << endl;
}

void ListTest::simpleOperation()
{
    // create two empty lists
    list<int> list1, list2;

    // fill both lists with elements
    for (int i = 0; i<6; ++i) {
        list1.push_back(i);
        list2.push_front(i);
    }
    printLists(list1, list2);

    // insert all elements of list1 before the first element with value 3 of list2
    // - find() returns an iterator to the first element with value 3
    list2.splice(find(list2.begin(), list2.end(),  // destination position
        3),
        list1);                          // source list
    printLists(list1, list2);

    // move first element of list2 to the end
    list2.splice(list2.end(),        // destination position
        list2,              // source list
        list2.begin());     // source position
    printLists(list1, list2);

    // sort second list, assign to list1 and remove duplicates
    list2.sort();
    list1 = list2;
    list2.unique();
    printLists(list1, list2);

    // merge both sorted lists into the first list
    list1.merge(list2);
    printLists(list1, list2);

    // remove all even elements
    list1.remove_if([](int i) {
        return i % 2 == 0;
    });
    printLists(list1, list2);
}

void ListTest::run()
{
    printStart("simpleOperation()");
    simpleOperation();
    printEnd("simpleOperation()");
}

运行结果:

---------------- simpleOperation(): Run Start ----------------
list1: 0 1 2 3 4 5
list2: 5 4 3 2 1 0

list1:
list2: 5 4 0 1 2 3 4 5 3 2 1 0

list1:
list2: 4 0 1 2 3 4 5 3 2 1 0 5

list1: 0 0 1 1 2 2 3 3 4 4 5 5
list2: 0 1 2 3 4 5

list1: 0 0 0 1 1 1 2 2 2 3 3 3 4 4 4 5 5 5
list2:

list1: 1 1 1 3 3 3 5 5 5
list2:

---------------- simpleOperation(): Run End ----------------