产品开发管理_上海娱乐场所关闭_网络服务器价格_百度账号客服人工电话

1.简介

list：带头双向循环链表

2.遍历方式

void test_list1()
{list<int> lt;lt.push_back(1);lt.push_back(2);lt.push_back(3);lt.push_back(4);lt.push_back(5);//遍历方式，不再支持[]//当然是可以支持的，但效率过低list<int>::iterator it = lt.begin();//迭代器是属于内嵌类型，一般使用typedef或是内部类的方式实现//list的迭代器更加复杂，就不是原生指针了while (it != lt.end()){cout << *(it++) << " ";}cout << endl;//底层就是迭代器，编译会器把范围for替换成迭代器for (auto e : lt){cout << e << " ";}cout << endl;
}

3.构造

4. Modifiers

4.1 assign

4.2 insert

5. Operations

5.1 reverse

void test_list2()
{list<int> lt;lt.push_back(1);lt.push_back(2);lt.push_back(3);lt.push_back(4);lt.push_back(5);for (auto e : lt){cout << e << " ";}cout << endl;lt.reverse();//逆置for (auto e : lt){cout << e << " ";}cout << endl;}

5.2 sort

为什么算法库中有sort，list还要单独写个sort

算法库的sort

list的sort

void test_list2()
{list<int> lt;lt.push_back(5);lt.push_back(4);lt.push_back(3);lt.push_back(2);lt.push_back(1);//sort(lt.begin(), lt.end());//使用时要包含头文件<algorithm>lt.sort();//默认是升序for (auto e : lt){cout << e << " ";}cout << endl;//升序 < less//如果想排降序 > greater// 1.//greater<int> gt;//lt.sort(gt);//2.lt.sort(greater<int>());//使用匿名对象for (auto e : lt){cout << e << " ";}cout << endl;}

5.2.1比较库中与list中sort的性能差异

//注意：测试性能时要切换为release
void test_op()
{srand(time(0));const int N = 100000;vector<int> v;list<int> lt1;for (int i = 0; i < N; ++i){auto e = rand();lt1.push_back(e);v.push_back(e);}//1.库中的sortint begin1 = clock();sort(v.begin(),v.end());int end1 = clock();//2.list的sortint begin2 = clock();lt1.sort();int end2 = clock();printf("vector sort:%d\n", end1 - begin1);printf("list sort:%d\n", end2 - begin2);
}

结论：库中的sort性能更好

//实际上，list的排序是很无用的
void test_op()
{srand(time(0));const int N = 1000000;list<int> lt1;list<int> lt2;for (int i = 0; i < N; ++i){auto e = rand();lt1.push_back(e);lt2.push_back(e);}//int begin1 = clock();//1.先拷贝到vectorvector<int> v(lt2.begin(),lt2.end());//2.排序sort(v.begin(),v.end());//3.拷贝回lt2lt2.assign(v.begin(), v.end());int end1 = clock();int begin2 = clock();lt1.sort();int end2 = clock();printf("list copy vector sort copy list sort:%d\n", end1 - begin1);//哪怕是这样，库中的sort性能也更好//也说明了拷贝数据的代价并没有很大printf("list sort:%d\n", end2 - begin2);
}

list中sort的优势就是方便一些，数据量少时可以使用

5.3 merge

5.4 unique

void test_list3()
{list<int> lt;lt.push_back(1);lt.push_back(2);lt.push_back(2);lt.push_back(2);lt.push_back(3);lt.push_back(4);lt.push_back(5);lt.push_back(5);lt.push_back(5);for (auto e : lt){cout << e << " ";}cout << endl;lt.unique();for (auto e : lt){cout << e << " ";}cout << endl;
}

5.5 remove

void test_list3()
{list<int> lt;lt.push_back(1);lt.push_back(2);lt.push_back(2);lt.push_back(2);lt.push_back(3);lt.push_back(4);lt.push_back(5);lt.push_back(5);lt.push_back(5);for (auto e : lt){cout << e << " ";}cout << endl;lt.remove(2);lt.remove(30);//如果remove一个不存在的值，就什么也不会做for (auto e : lt){cout << e << " ";}cout << endl;
}

5.6 splice

void test_list4()
{std::list<int> mylist1, mylist2;std::list<int>::iterator it;// set some initial values:for (int i = 1; i <= 4; ++i)mylist1.push_back(i);      // mylist1: 1 2 3 4for (int i = 1; i <= 3; ++i)mylist2.push_back(i * 10);   // mylist2: 10 20 30for (auto e : mylist1){cout << e << " ";}cout << endl;for (auto e : mylist2){cout << e << " ";}cout << endl;it = mylist1.begin();++it;                         // points to 2mylist1.splice(it, mylist2); // mylist1: 1 10 20 30 2 3 4// mylist2 (empty)// "it" still points to 2 (the 5th element)for (auto e : mylist1){cout << e << " ";}cout << endl;for (auto e : mylist2){cout << e << " ";}cout << endl;
}