05-11 03:16 阅读 179

16.7.2【列表list容器的赋值和交换、大小操作】

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<code-pre class="code-pre" id="pre-ZnQTsw"><code-line class="line-numbers-rows"></code-line>#include<iostream>

<code-line class="line-numbers-rows"></code-line>#include<cstdlib>

<code-line class="line-numbers-rows"></code-line>using namespace std;

<code-line class="line-numbers-rows"></code-line>#include <list>

<code-line class="line-numbers-rows"></code-line>

<code-line class="line-numbers-rows"></code-line>/*

<code-line class="line-numbers-rows"></code-line> 3.7.3 list赋值和交换

<code-line class="line-numbers-rows"></code-line>

<code-line class="line-numbers-rows"></code-line> 给list容器进行赋值，以及交换list容器

<code-line class="line-numbers-rows"></code-line>

<code-line class="line-numbers-rows"></code-line>        assign(beg, end); //将[beg, end)区间中的数据拷贝赋值给本身。

<code-line class="line-numbers-rows"></code-line> assign(n, elem); //将n个elem拷贝赋值给本身。

<code-line class="line-numbers-rows"></code-line>        list& operator=(const list &lst); //重载等号操作符。

<code-line class="line-numbers-rows"></code-line> swap(lst); //将lst与本身的元素互换。

<code-line class="line-numbers-rows"></code-line>

<code-line class="line-numbers-rows"></code-line> 3.7.4 list大小操作

<code-line class="line-numbers-rows"></code-line>

<code-line class="line-numbers-rows"></code-line> 对list容器的大小进行操作

<code-line class="line-numbers-rows"></code-line>

<code-line class="line-numbers-rows"></code-line> size(); //返回容器中元素的个数

<code-line class="line-numbers-rows"></code-line> empty(); //判断容器是否为空

<code-line class="line-numbers-rows"></code-line>        resize(num); //重新指定容器的长度为num，若容器变长，则以默认值填充新位置。

<code-line class="line-numbers-rows"></code-line>                     //如果容器变短，则末尾超出容器长度的元素被删除。

<code-line class="line-numbers-rows"></code-line>        resize(num, elem); //重新指定容器的长度为num，若容器变长，则以elem值填充新位置。

<code-line class="line-numbers-rows"></code-line>                           //如果容器变短，则末尾超出容器长度的元素被删除。

<code-line class="line-numbers-rows"></code-line>*/

<code-line class="line-numbers-rows"></code-line>

<code-line class="line-numbers-rows"></code-line>void print_list(const list<int> & L)

<code-line class="line-numbers-rows"></code-line>{

<code-line class="line-numbers-rows"></code-line> for(list<int>::const_iterator cit=L.begin(); cit!=L.end(); cit++)

<code-line class="line-numbers-rows"></code-line> {

<code-line class="line-numbers-rows"></code-line> cout << *cit << " ";

<code-line class="line-numbers-rows"></code-line> }

<code-line class="line-numbers-rows"></code-line> cout << endl;

<code-line class="line-numbers-rows"></code-line>}

<code-line class="line-numbers-rows"></code-line>

<code-line class="line-numbers-rows"></code-line>void test373_1()

<code-line class="line-numbers-rows"></code-line>{

<code-line class="line-numbers-rows"></code-line> list<int> l1;

<code-line class="line-numbers-rows"></code-line> l1.push_back(10);

<code-line class="line-numbers-rows"></code-line> l1.push_back(20);

<code-line class="line-numbers-rows"></code-line> l1.push_back(30);

<code-line class="line-numbers-rows"></code-line> l1.push_back(40);

<code-line class="line-numbers-rows"></code-line> print_list(l1);

<code-line class="line-numbers-rows"></code-line>

<code-line class="line-numbers-rows"></code-line> //赋值

<code-line class="line-numbers-rows"></code-line> list<int> l2;

<code-line class="line-numbers-rows"></code-line> l2 = l1;

<code-line class="line-numbers-rows"></code-line> print_list(l2);

<code-line class="line-numbers-rows"></code-line>

<code-line class="line-numbers-rows"></code-line> list<int> l3;

<code-line class="line-numbers-rows"></code-line> l3.assign(l1.begin(), l1.end());

<code-line class="line-numbers-rows"></code-line> print_list(l3);

<code-line class="line-numbers-rows"></code-line>

<code-line class="line-numbers-rows"></code-line> list<int> l4;

<code-line class="line-numbers-rows"></code-line> l4.assign(10, 999);

<code-line class="line-numbers-rows"></code-line> print_list(l4);

<code-line class="line-numbers-rows"></code-line>}

<code-line class="line-numbers-rows"></code-line>

<code-line class="line-numbers-rows"></code-line>void test373_2()

<code-line class="line-numbers-rows"></code-line>{

<code-line class="line-numbers-rows"></code-line> list<int> l1;

<code-line class="line-numbers-rows"></code-line> l1.push_back(10);

<code-line class="line-numbers-rows"></code-line> l1.push_back(20);

<code-line class="line-numbers-rows"></code-line> l1.push_back(30);

<code-line class="line-numbers-rows"></code-line> l1.push_back(40);

<code-line class="line-numbers-rows"></code-line>

<code-line class="line-numbers-rows"></code-line> list<int> l2;

<code-line class="line-numbers-rows"></code-line> l2.assign(10, 999);

<code-line class="line-numbers-rows"></code-line>

<code-line class="line-numbers-rows"></code-line> cout << "交换前：" << endl;

<code-line class="line-numbers-rows"></code-line> print_list(l1);

<code-line class="line-numbers-rows"></code-line> print_list(l2);

<code-line class="line-numbers-rows"></code-line>

<code-line class="line-numbers-rows"></code-line> l1.swap(l2); //互换

<code-line class="line-numbers-rows"></code-line>

<code-line class="line-numbers-rows"></code-line> cout << "交换后：" << endl;

<code-line class="line-numbers-rows"></code-line> print_list(l1);

<code-line class="line-numbers-rows"></code-line> print_list(l2);

<code-line class="line-numbers-rows"></code-line>}

<code-line class="line-numbers-rows"></code-line>

<code-line class="line-numbers-rows"></code-line>void test374()

<code-line class="line-numbers-rows"></code-line>{

<code-line class="line-numbers-rows"></code-line> list<int> l1;

<code-line class="line-numbers-rows"></code-line> l1.push_back(10);

<code-line class="line-numbers-rows"></code-line> l1.push_back(20);

<code-line class="line-numbers-rows"></code-line> l1.push_back(30);

<code-line class="line-numbers-rows"></code-line> l1.push_back(40);

<code-line class="line-numbers-rows"></code-line> print_list(l1);

<code-line class="line-numbers-rows"></code-line>

<code-line class="line-numbers-rows"></code-line> if(l1.empty())

<code-line class="line-numbers-rows"></code-line> {

<code-line class="line-numbers-rows"></code-line> cout << "l1为空" << endl;

<code-line class="line-numbers-rows"></code-line> }

<code-line class="line-numbers-rows"></code-line> else

<code-line class="line-numbers-rows"></code-line> {

<code-line class="line-numbers-rows"></code-line> cout << "l1不为空" << endl;

<code-line class="line-numbers-rows"></code-line> cout << "l1元素个数：" << l1.size() << endl;

<code-line class="line-numbers-rows"></code-line> }

<code-line class="line-numbers-rows"></code-line>

<code-line class="line-numbers-rows"></code-line> l1.resize(10); //新指定大小 > 原大小，默认用0填充多出来的位置

<code-line class="line-numbers-rows"></code-line> print_list(l1);

<code-line class="line-numbers-rows"></code-line> l1.resize(20, 8); //新指定大小 > 原大小，指定值8填充多出来的位置

<code-line class="line-numbers-rows"></code-line> print_list(l1);

<code-line class="line-numbers-rows"></code-line> l1.resize(2); //新指定大小 < 原大小，删除多出来的元素

<code-line class="line-numbers-rows"></code-line> print_list(l1);

<code-line class="line-numbers-rows"></code-line>}

<code-line class="line-numbers-rows"></code-line>

<code-line class="line-numbers-rows"></code-line>int main()

<code-line class="line-numbers-rows"></code-line>{

<code-line class="line-numbers-rows"></code-line> test373_1();

<code-line class="line-numbers-rows"></code-line> test373_2();

<code-line class="line-numbers-rows"></code-line> test374();

<code-line class="line-numbers-rows"></code-line>

<code-line class="line-numbers-rows"></code-line> system("pause");

<code-line class="line-numbers-rows"></code-line> return 0;

<code-line class="line-numbers-rows"></code-line>}

</code-pre>

来源：https://www.cnblogs.com/yppah/p/14755277.html

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