侯捷STL学习(一)--顺序容器测试

开始跟着《STL源码剖析》的作者侯捷真人视频，学习STL,了解STL背后的真实故事！
视频链接：侯捷STL
还有很大其他视频需要的留言

第一节：STL版本和重要资源

STL和标准库的区别

侯捷STL学习(一)--顺序容器测试

三个网站

第二节：STL六大部件

迭代器将容器和算法结合起来
分配器实现，适配器用的地方很多

侯捷STL学习(一)--顺序容器测试

实例：

侯捷STL学习(一)--顺序容器测试

理解容器的前闭后开的设计。迭代器类似于指针，很多操作和指针差不多++,--运算。vec.begin(),vec.end()指向容器最后一个元素的下一个位置，解引用*（vec.end()）错误！
auto关键字的应用

std::vector<double> vec;

for(auto elem: vec)

{

   std::cout<<elem<<std::endl;

}

第三节：容器之分类和各种测试（一）

分类结构

红色框中标注的是C++11开始有的容器
Array数组容器，大小固定的
Deque:两段都可以进行插入删除操作，但是从内存上讲不通，怎么实现的要从后面的学习知道。
List:是一个双向的循环链表，注意是双向的。
Forward-List:单向链表，当能用单向链表的时候尽量用，可以减少内存空间，一个指针在32位pc上占4个字节，当数据量很多上百万，不可忽略！
Set键值都一样，MultiSet允许元素有重复。
Set/Map用红黑树实现，RB-tree是自平衡的二叉树。
Unorder Containers:是C++标准库里卖的内容。
根据这些图例，可以知道这些容器在内存用到的数据结构是什么样的。
HashTable实现方法很多，但基本都用Separate Chaining(分离链地址法实现)。

侯捷STL学习(一)--顺序容器测试

测试Array

指针void* a -> *(long*)a;
array<long, size> c使用初始化大小，#include<array>
c.data()返回这个数组的初始地址，和数组的地址对比
qsort应用：qsort(c.data,size,size(long),comparelongs)
bsearch()应用,查找前必须排好序了：bsearch(&target,(c.data()),size,size(long),comparelongs)
qsort,bsearch包含头文件#include<cstdlib>，C本身库函数

#include <array>

#include <iostream>

#include <ctime>

#include <cstdlib> //qsort, bsearch, NULL

namespace jj01

{

void test_array()

{

	cout << "\ntest_array().......... \n";

array<long,ASIZE> c;  	

clock_t timeStart = clock();

    for(long i=0; i< ASIZE; ++i) {

        c[i] = rand();

    }

	cout << "milli-seconds : " << (clock()-timeStart) << endl;	//

	cout << "array.size()= " << c.size() << endl;

	cout << "array.front()= " << c.front() << endl;

	cout << "array.back()= " << c.back() << endl;

	cout << "array.data()= " << c.data() << endl;	

long target = get_a_target_long();

	timeStart = clock();

    ::qsort(c.data(), ASIZE, sizeof(long), compareLongs);

long* pItem = (long*)::bsearch(&target, (c.data()), ASIZE, sizeof(long), compareLongs);

	cout << "qsort()+bsearch(), milli-seconds : " << (clock()-timeStart) << endl;	//

  	if (pItem != NULL)

    	cout << "found, " << *pItem << endl;

  	else

    	cout << "not found! " << endl;

}

}

第四节：容器之分类和各种测试（二）

测试Vector

主要通过程序细节说明
namespace命名空间的说明
vector的增长速度是2倍增长，当capacity不够时，容量增长为前面的2倍。是在另外的2倍空间！
try...catch...捕获函数，字符串最大占一个指针大小，空间不够的时候抛出，abort()退出
::find()模板函数，加冒号表明是全局函数，当没有冒号时，编译器在当前没有找到，也会到全局去找。
用两种查找算法比较，find()用时更少。

#include <vector>

#include <stdexcept>

#include <string>

#include <cstdlib> //abort()   //qsort, bsearch, NULL

#include <cstdio>  //snprintf()

#include <iostream>

#include <ctime>

#include <algorithm> 	//sort()

namespace jj02

{

void test_vector(long& value)

{

	cout << "\ntest_vector().......... \n";

vector<string> c;

char buf[10];

clock_t timeStart = clock();

    for(long i=0; i< value; ++i)

    {

    	try {

    		snprintf(buf, 10, "%d", rand());

        	c.push_back(string(buf));

		}

		catch(exception& p) {

			cout << "i=" << i << " " << p.what() << endl;

			     //曾經最高 i=58389486 then std::bad_alloc

			abort();

		}

	}

	cout << "milli-seconds : " << (clock()-timeStart) << endl;

	cout << "vector.max_size()= " << c.max_size() << endl;	//1073747823

	cout << "vector.size()= " << c.size() << endl;

	cout << "vector.front()= " << c.front() << endl;

	cout << "vector.back()= " << c.back() << endl;

	cout << "vector.data()= " << c.data() << endl;

	cout << "vector.capacity()= " << c.capacity() << endl << endl;		

string target = get_a_target_string();

    {

	timeStart = clock();

auto pItem = find(c.begin(), c.end(), target);

	cout << "std::find(), milli-seconds : " << (clock()-timeStart) << endl;  

  	if (pItem != c.end())

    	cout << "found, " << *pItem << endl << endl;

  	else

    	cout << "not found! " << endl << endl;

    }

	{

	timeStart = clock();

    sort(c.begin(), c.end());

	cout << "sort(), milli-seconds : " << (clock()-timeStart) << endl; 

	timeStart = clock();

string* pItem = (string*)::bsearch(&target, (c.data()),

                                   c.size(), sizeof(string), compareStrings);

	cout << "bsearch(), milli-seconds : " << (clock()-timeStart) << endl; 

  	if (pItem != NULL)

    	cout << "found, " << *pItem << endl << endl;

  	else

    	cout << "not found! " << endl << endl;

	}

	c.clear();

	test_moveable(vector<MyString>(),vector<MyStrNoMove>(), value);

}

}

第五节：容器之分类和各种测试（三）

测试List，双向链表

list.max_size()按理list是动态申请空间的，为什么最大的size呢？
list双向链表实现
有趣的c.sort(),这里注意在STL标准库全局有一个sort函数，但这里调用的是list容器自身内部的sort函数。注意在STL容器中有些自身有sort函数，此时用自身的排序算法更快。

#include <list>

#include <stdexcept>

#include <string>

#include <cstdlib> //abort()

#include <cstdio>  //snprintf()

#include <algorithm> //find()

#include <iostream>

#include <ctime>

namespace jj03

{

void test_list(long& value)

{

	cout << "\ntest_list().......... \n";

list<string> c;

char buf[10];

clock_t timeStart = clock();

    for(long i=0; i< value; ++i)

    {

    	try {

    		snprintf(buf, 10, "%d", rand());

        	c.push_back(string(buf));

		}

		catch(exception& p) {

			cout << "i=" << i << " " << p.what() << endl;

			abort();

		}

	}

	cout << "milli-seconds : " << (clock()-timeStart) << endl;

	cout << "list.size()= " << c.size() << endl;

	cout << "list.max_size()= " << c.max_size() << endl;    //357913941

	cout << "list.front()= " << c.front() << endl;

	cout << "list.back()= " << c.back() << endl;		

string target = get_a_target_string();

    timeStart = clock();

auto pItem = find(c.begin(), c.end(), target);

	cout << "std::find(), milli-seconds : " << (clock()-timeStart) << endl;		

  	if (pItem != c.end())

    	cout << "found, " << *pItem << endl;

  	else

    	cout << "not found! " << endl;	

    timeStart = clock();

	c.sort();

	cout << "c.sort(), milli-seconds : " << (clock()-timeStart) << endl;		    	

	c.clear();

	test_moveable(list<MyString>(),list<MyStrNoMove>(), value);

}

}

测试forward-list，单向链表

forward-list单向链表，C++11出现的
push_front在链表头插入，不提供在尾部插入，效率低些。
front取链表头的元素，不提供back()操作取链表尾的元素。
c.sort()用它自身的排序算法

#include <forward_list>

#include <stdexcept>

#include <string>

#include <cstdlib> //abort()

#include <cstdio>  //snprintf()

#include <iostream>

#include <ctime>

namespace jj04

{

void test_forward_list(long& value)

{

	cout << "\ntest_forward_list().......... \n";

forward_list<string> c;

char buf[10];

clock_t timeStart = clock();

    for(long i=0; i< value; ++i)

    {

    	try {

    		snprintf(buf, 10, "%d", rand());

        	c.push_front(string(buf));

		}

		catch(exception& p) {

			cout << "i=" << i << " " << p.what() << endl;

			abort();

		}

	}

	cout << "milli-seconds : " << (clock()-timeStart) << endl;

	cout << "forward_list.max_size()= " << c.max_size() << endl;  //536870911

	cout << "forward_list.front()= " << c.front() << endl;	

string target = get_a_target_string();

    timeStart = clock();

auto pItem = find(c.begin(), c.end(), target);

	cout << "std::find(), milli-seconds : " << (clock()-timeStart) << endl;		

	if (pItem != c.end())

    	cout << "found, " << *pItem << endl;

  	else

    	cout << "not found! " << endl;	

    timeStart = clock();

	c.sort();

	cout << "c.sort(), milli-seconds : " << (clock()-timeStart) << endl;		

	c.clear();

}

}

测试slist

Gnu C之前的单链表,forward-list是C++11才出现的
#include<ext\slist>头文件

#include <ext\slist>

	//注意, 上一行並沒有引發警告訊息如 #include <ext\hash_set> 所引發者：

	//...\4.9.2\include\c++\backward\backward_warning.h

	//[Warning] ...

#include <stdexcept>

#include <string>

#include <cstdlib> //abort()

#include <cstdio>  //snprintf()

#include <iostream>

#include <ctime>

namespace jj10

{

void test_slist(long& value)

{

	cout << "\ntest_slist().......... \n";

	__gnu_cxx::slist<string> c;

	char buf[10];

    clock_t timeStart = clock();

    for(long i=0; i< value; ++i)

    {

    	try {

    		snprintf(buf, 10, "%d", rand());

        	c.push_front(string(buf));

		}

		catch(exception& p) {

			cout << "i=" << i << " " << p.what() << endl;

			abort();

		}

	}

	cout << "milli-seconds : " << (clock()-timeStart) << endl;

}

}

测试deque

双向开口，是分段连续，感觉是连续的，其实不是。
内存上两边都可以扩充
每次512扩充，两边扩充申请buffer,buffer由指针指向
max_size由限制，使用全局的sort排序

侯捷STL学习(一)--顺序容器测试

#include <deque>

#include <stdexcept>

#include <string>

#include <cstdlib> //abort()

#include <cstdio>  //snprintf()

#include <iostream>

#include <ctime>

namespace jj05

{

void test_deque(long& value)

{

	cout << "\ntest_deque().......... \n";

deque<string> c;

char buf[10];

clock_t timeStart = clock();

    for(long i=0; i< value; ++i)

    {

    	try {

    		snprintf(buf, 10, "%d", rand());

        	c.push_back(string(buf));

		}

		catch(exception& p) {

			cout << "i=" << i << " " << p.what() << endl;

			abort();

		}

	}

	cout << "milli-seconds : " << (clock()-timeStart) << endl;

	cout << "deque.size()= " << c.size() << endl;

	cout << "deque.front()= " << c.front() << endl;

	cout << "deque.back()= " << c.back() << endl;

	cout << "deque.max_size()= " << c.max_size() << endl;	//1073741821	

string target = get_a_target_string();

    timeStart = clock();

auto pItem = find(c.begin(), c.end(), target);

	cout << "std::find(), milli-seconds : " << (clock()-timeStart) << endl;	

	if (pItem != c.end())

    	cout << "found, " << *pItem << endl;

  	else

    	cout << "not found! " << endl;	

    timeStart = clock();

	sort(c.begin(), c.end());

	cout << "sort(), milli-seconds : " << (clock()-timeStart) << endl;		

	c.clear();

	test_moveable(deque<MyString>(),deque<MyStrNoMove>(), value);

}

}

测试stack

栈,数据结构上和deque差不多
两段插入插入删除受限的容器
也有人叫做容器的适配器adapter
没有提供容器的迭代器iterator,否则对迭代器的操作会破坏堆栈的结构
也没有提供find,sort的功能；但是有时候让你实现堆栈的排序操作

侯捷STL学习(一)--顺序容器测试

#include <stack>

#include <stdexcept>

#include <string>

#include <cstdlib> //abort()

#include <cstdio>  //snprintf()

#include <iostream>

#include <ctime>

namespace jj17

{

void test_stack(long& value)

{

	cout << "\ntest_stack().......... \n";

stack<string> c;

char buf[10];

clock_t timeStart = clock();

    for(long i=0; i< value; ++i)

    {

    	try {

    		snprintf(buf, 10, "%d", rand());

        	c.push(string(buf));

		}

		catch(exception& p) {

			cout << "i=" << i << " " << p.what() << endl;

			abort();

		}

	}

	cout << "milli-seconds : " << (clock()-timeStart) << endl;

	cout << "stack.size()= " << c.size() << endl;

	cout << "stack.top()= " << c.top() << endl;

	c.pop();

	cout << "stack.size()= " << c.size() << endl;

	cout << "stack.top()= " << c.top() << endl;	

	{

stack<string, list<string>> c;		//以 list 為底層

    for(long i=0; i< 10; ++i) {

    		snprintf(buf, 10, "%d", rand());

        	c.push(string(buf));

	}

	cout << "stack.size()= " << c.size() << endl;

	cout << "stack.top()= " << c.top() << endl;

	c.pop();

	cout << "stack.size()= " << c.size() << endl;

	cout << "stack.top()= " << c.top() << endl;

    }	

	{

stack<string, vector<string>> c;	//以 vector 為底層

    for(long i=0; i< 10; ++i) {

    		snprintf(buf, 10, "%d", rand());

        	c.push(string(buf));

	}

	cout << "stack.size()= " << c.size() << endl;

	cout << "stack.top()= " << c.top() << endl;

	c.pop();

	cout << "stack.size()= " << c.size() << endl;

	cout << "stack.top()= " << c.top() << endl;

    }

	{

stack<string, set<string>> c;	//以 set 為底層

/*!

    for(long i=0; i< 10; ++i) {

    		snprintf(buf, 10, "%d", rand());

        	c.push(string(buf));

	}

	cout << "stack.size()= " << c.size() << endl;

	cout << "stack.top()= " << c.top() << endl;

	c.pop();

	cout << "stack.size()= " << c.size() << endl;

	cout << "stack.top()= " << c.top() << endl;	

//[Error] 'class std::set<std::basic_string<char> >' has no member named 'push_back'

//[Error] 'class std::set<std::basic_string<char> >' has no member named 'back'

//[Error] 'class std::set<std::basic_string<char> >' has no member named 'pop_back'

*/

    }

//!stack<string, map(string>> c5;	////以 map 為底層, [Error] template argument 2 is invalid

//!stack<string>::iterator ite1;  	//[Error] 'iterator' is not a member of 'std::stack<std::basic_string<char> >'

}

}

测试queue

堆，数据结构上有deque衍生出来的
没有提供容器的迭代器iterator,否则对迭代器的操作会破坏堆栈的结构

侯捷STL学习(一)--顺序容器测试

#include <queue>

#include <stdexcept>

#include <string>

#include <cstdlib> //abort()

#include <cstdio>  //snprintf()

#include <iostream>

#include <ctime>

namespace jj18

{

void test_queue(long& value)

{

	cout << "\ntest_queue().......... \n";

queue<string> c;

char buf[10];

clock_t timeStart = clock();

    for(long i=0; i< value; ++i)

    {

    	try {

    		snprintf(buf, 10, "%d", rand());

        	c.push(string(buf));

		}

		catch(exception& p) {

			cout << "i=" << i << " " << p.what() << endl;

			abort();

		}

	}

	cout << "milli-seconds : " << (clock()-timeStart) << endl;

	cout << "queue.size()= " << c.size() << endl;

	cout << "queue.front()= " << c.front() << endl;

	cout << "queue.back()= " << c.back() << endl;

	c.pop();

	cout << "queue.size()= " << c.size() << endl;

	cout << "queue.front()= " << c.front() << endl;

	cout << "queue.back()= " << c.back() << endl;	

	{

queue<string, list<string>> c;		//以 list 為底層

    for(long i=0; i< 10; ++i) {

    		snprintf(buf, 10, "%d", rand());

        	c.push(string(buf));

	}

	cout << "queue.size()= " << c.size() << endl;

	cout << "queue.front()= " << c.front() << endl;

	cout << "queue.back()= " << c.back() << endl;

	c.pop();

	cout << "queue.size()= " << c.size() << endl;

	cout << "queue.front()= " << c.front() << endl;

	cout << "queue.back()= " << c.back() << endl;

    }	

	{

queue<string, vector<string>> c;	//以 vector 為底層

    for(long i=0; i< 10; ++i) {

    		snprintf(buf, 10, "%d", rand());

        	c.push(string(buf));

	}

	cout << "queue.size()= " << c.size() << endl;

	cout << "queue.front()= " << c.front() << endl;

	cout << "queue.back()= " << c.back() << endl;

	//!c.pop();  //[Error] 'class std::vector<std::basic_string<char> >' has no member named 'pop_front'

	cout << "queue.size()= " << c.size() << endl;

	cout << "queue.front()= " << c.front() << endl;

	cout << "queue.back()= " << c.back() << endl;

    }	

	{

queue<string, set<string>> c;		//以 set 為底層

/*!

    for(long i=0; i< 10; ++i) {

    		snprintf(buf, 10, "%d", rand());

        	c.push(string(buf));

	}

	cout << "queue.size()= " << c.size() << endl;

	cout << "queue.front()= " << c.front() << endl;

	cout << "queue.back()= " << c.back() << endl;

	c.pop();

	cout << "queue.size()= " << c.size() << endl;

	cout << "queue.front()= " << c.front() << endl;

	cout << "queue.back()= " << c.back() << endl;

//[Error] 'class std::set<std::basic_string<char> >' has no member named 'push_back'

//[Error] 'class std::set<std::basic_string<char> >' has no member named 'front'

//[Error] 'class std::set<std::basic_string<char> >' has no member named 'pop_front'

*/

    }

//! queue<string, map<string>> c5;	//以 map 為底層, [Error] template argument 2 is invalid

//! queue<string>::iterator ite1;  	//[Error] 'iterator' is not a member of 'std::queue<std::basic_string<char> >'

}

}

秒客网

侯捷STL学习(一)--顺序容器测试

第一节：STL版本和重要资源

第二节：STL六大部件

第三节：容器之分类和各种测试（一）

分类结构

测试Array

第四节：容器之分类和各种测试（二）

测试Vector

第五节：容器之分类和各种测试（三）

测试List，双向链表

测试forward-list，单向链表

测试slist

测试deque

测试stack

测试queue

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