侯捷STL学习(二)--序列容器测试

第六节：容器之分类和各种测试（四）

• stack不提供iterator操作，破坏了容器的独特性，先进先出。

使用容器multiset（允许元素重复）

• 内部是红黑树，insert操作就保证了排好了序。
• 标准库有个：：find()函数，大家都可以用。容器本身也有一个c.find()，通过键值对查找非常快！
• 测试

#include <set>
#include <stdexcept>
#include <string>
#include <cstdlib> //abort()
#include <cstdio>  //snprintf()
#include <iostream>
#include <ctime>
namespace jj06
{
void test_multiset(long& value)
{
	cout << "\ntest_multiset().......... \n";

multiset<string> c;
char buf[10];
clock_t timeStart = clock();
    for(long i=0; i< value; ++i)
    {
    	try {
    		snprintf(buf, 10, "%d", rand());
        	c.insert(string(buf));
		}
		catch(exception& p) {
			cout << "i=" << i << " " << p.what() << endl;
			abort();
		}
	}
	cout << "milli-seconds : " << (clock()-timeStart) << endl;
	cout << "multiset.size()= " << c.size() << endl;
	cout << "multiset.max_size()= " << c.max_size() << endl;	//214748364

string target = get_a_target_string();
	{
    timeStart = clock();
auto pItem = find(c.begin(), c.end(), target);	//比 c.find(...) 慢很多
	cout << "std::find(), milli-seconds : " << (clock()-timeStart) << endl;
	if (pItem != c.end())
    	cout << "found, " << *pItem << endl;
  	else
    	cout << "not found! " << endl;
 	}

 	{
    timeStart = clock();
auto pItem = c.find(target);		//比 std::find(...) 快很多
	cout << "c.find(), milli-seconds : " << (clock()-timeStart) << endl;
	if (pItem != c.end())
    	cout << "found, " << *pItem << endl;
  	else
    	cout << "not found! " << endl;
 	}	

	c.clear();
	test_moveable(multiset<MyString>(),multiset<MyStrNoMove>(), value);
}
}

使用容器multimap（允许元素重复）

• 内部是红黑树，key-value键值对。
• multiset不可用[]做insertion
• c.insert(pair<long,string>(i,buff))
• (*pItem).second
• 测试

#include <map>
#include <stdexcept>
#include <string>
#include <cstdlib> //abort()
#include <cstdio>  //snprintf()
#include <iostream>
#include <ctime>
namespace jj07
{
void test_multimap(long& value)
{
	cout << "\ntest_multimap().......... \n";

multimap<long, string> c;
char buf[10];

clock_t timeStart = clock();
    for(long i=0; i< value; ++i)
    {
    	try {
    		snprintf(buf, 10, "%d", rand());
    		//multimap 不可使用 [] 做 insertion
        	c.insert(pair<long,string>(i,buf));
		}
		catch(exception& p) {
			cout << "i=" << i << " " << p.what() << endl;
			abort();
		}
	}
	cout << "milli-seconds : " << (clock()-timeStart) << endl;
	cout << "multimap.size()= " << c.size() << endl;
	cout << "multimap.max_size()= " << c.max_size() << endl;	//178956970	

long target = get_a_target_long();
    timeStart = clock();
auto pItem = c.find(target);
	cout << "c.find(), milli-seconds : " << (clock()-timeStart) << endl;
	if (pItem != c.end())
    	cout << "found, value=" << (*pItem).second << endl;
  	else
    	cout << "not found! " << endl;	  

	c.clear();
}
}

使用unordered_multiset容器

• 使用hashtable使用分离链地址方法实现
• gnu C之前的名称hash_multiset
• unorder_multiset.bucket_count篮子的个数
• load_factor,max_load_factor,max_bucket_count方法
• 篮子后面的链表不能太长，元素的个数大于等于篮子的个数，就需要重新分配篮子的大小，重新进行插入元素
• c.find()容器自身的find操作快很多
• 测试

#include <unordered_set>
#include <stdexcept>
#include <string>
#include <cstdlib> //abort()
#include <cstdio>  //snprintf()
#include <iostream>
#include <ctime>
namespace jj08
{
void test_unordered_multiset(long& value)
{
	cout << "\ntest_unordered_multiset().......... \n";

unordered_multiset<string> c;
char buf[10];

clock_t timeStart = clock();
    for(long i=0; i< value; ++i)
    {
    	try {
    		snprintf(buf, 10, "%d", rand());
        	c.insert(string(buf));
		}
		catch(exception& p) {
			cout << "i=" << i << " " << p.what() << endl;
			abort();
		}
	}
	cout << "milli-seconds : " << (clock()-timeStart) << endl;
	cout << "unordered_multiset.size()= " << c.size() << endl;
	cout << "unordered_multiset.max_size()= " << c.max_size() << endl;	//357913941
	cout << "unordered_multiset.bucket_count()= " << c.bucket_count() << endl;
	cout << "unordered_multiset.load_factor()= " << c.load_factor() << endl;
	cout << "unordered_multiset.max_load_factor()= " << c.max_load_factor() << endl;
	cout << "unordered_multiset.max_bucket_count()= " << c.max_bucket_count() << endl;
  	for (unsigned i=0; i< 20; ++i) {
    	cout << "bucket #" << i << " has " << c.bucket_size(i) << " elements.\n";
  	}					

string target = get_a_target_string();
	{
    timeStart = clock();
auto pItem = find(c.begin(), c.end(), target);	//比 c.find(...) 慢很多
	cout << "std::find(), milli-seconds : " << (clock()-timeStart) << endl;
	if (pItem != c.end())
    	cout << "found, " << *pItem << endl;
  	else
    	cout << "not found! " << endl;
 	}

 	{
    timeStart = clock();
auto pItem = c.find(target);		//比 std::find(...) 快很多
	cout << "c.find(), milli-seconds : " << (clock()-timeStart) << endl;
	if (pItem != c.end())
    	cout << "found, " << *pItem << endl;
  	else
    	cout << "not found! " << endl;
 	}		

    c.clear();
	test_moveable(unordered_multiset<MyString>(),unordered_multiset<MyStrNoMove>(), value);
}
}

使用unordered_multimap容器

• 测试

#include <unordered_map>
#include <stdexcept>
#include <string>
#include <cstdlib> //abort()
#include <cstdio>  //snprintf()
#include <iostream>
#include <ctime>
namespace jj09
{
void test_unordered_multimap(long& value)
{
	cout << "\ntest_unordered_multimap().......... \n";

unordered_multimap<long, string> c;
char buf[10];

clock_t timeStart = clock();
    for(long i=0; i< value; ++i)
    {
    	try {
    		snprintf(buf, 10, "%d", rand());
			//multimap 不可使用 [] 進行 insertion
			c.insert(pair<long,string>(i,buf));
		}
		catch(exception& p) {
			cout << "i=" << i << " " << p.what() << endl;
			abort();
		}
	}
	cout << "milli-seconds : " << (clock()-timeStart) << endl;
	cout << "unordered_multimap.size()= " << c.size() << endl;
	cout << "unordered_multimap.max_size()= " << c.max_size() << endl;	//357913941	

long target = get_a_target_long();
    timeStart = clock();
auto pItem = c.find(target);
	cout << "c.find(), milli-seconds : " << (clock()-timeStart) << endl;
	if (pItem != c.end())
    	cout << "found, value=" << (*pItem).second << endl;
  	else
    	cout << "not found! " << endl;
}
}

使用set容器

• 不允许元素重复

#include <set>
#include <stdexcept>
#include <string>
#include <cstdlib> //abort()
#include <cstdio>  //snprintf()
#include <iostream>
#include <ctime>
namespace jj13
{
void test_set(long& value)
{
	cout << "\ntest_set().......... \n";

set<string> c;
char buf[10];

clock_t timeStart = clock();
    for(long i=0; i< value; ++i)
    {
    	try {
    		snprintf(buf, 10, "%d", rand());
        	c.insert(string(buf));
		}
		catch(exception& p) {
			cout << "i=" << i << " " << p.what() << endl;
			abort();
		}
	}
	cout << "milli-seconds : " << (clock()-timeStart) << endl;
	cout << "set.size()= " << c.size() << endl;
	cout << "set.max_size()= " << c.max_size() << endl;	   //214748364

string target = get_a_target_string();
	{
    timeStart = clock();
auto pItem = find(c.begin(), c.end(), target);	//比 c.find(...) 慢很多
	cout << "std::find(), milli-seconds : " << (clock()-timeStart) << endl;
	if (pItem != c.end())
    	cout << "found, " << *pItem << endl;
  	else
    	cout << "not found! " << endl;
 	}

 	{
    timeStart = clock();
auto pItem = c.find(target);		//比 std::find(...) 快很多
	cout << "c.find(), milli-seconds : " << (clock()-timeStart) << endl;
	if (pItem != c.end())
    	cout << "found, " << *pItem << endl;
  	else
    	cout << "not found! " << endl;
 	}
}
}

使用map容器

• 不允许元素键重复
• c[i]=string(buf)组成pair，允许这样进行插入操作

#include <map>
#include <stdexcept>
#include <string>
#include <cstdlib> //abort()
#include <cstdio>  //snprintf()
#include <iostream>
#include <ctime>
namespace jj14
{
void test_map(long& value)
{
	cout << "\ntest_map().......... \n";

map<long, string> c;
char buf[10];

clock_t timeStart = clock();
    for(long i=0; i< value; ++i)
    {
    	try {
    		snprintf(buf, 10, "%d", rand());
			c[i] = string(buf);
		}
		catch(exception& p) {
			cout << "i=" << i << " " << p.what() << endl;
			abort();
		}
	}
	cout << "milli-seconds : " << (clock()-timeStart) << endl;
	cout << "map.size()= " << c.size() << endl;
	cout << "map.max_size()= " << c.max_size() << endl;		//178956970

long target = get_a_target_long();
    timeStart = clock();
auto pItem = c.find(target);
	cout << "c.find(), milli-seconds : " << (clock()-timeStart) << endl;
	if (pItem != c.end())
    	cout << "found, value=" << (*pItem).second << endl;
  	else
    	cout << "not found! " << endl;			

    c.clear();
}
}

使用unorder_set容器

#include <unordered_set>
#include <stdexcept>
#include <string>
#include <cstdlib> //abort()
#include <cstdio>  //snprintf()
#include <iostream>
#include <ctime>
namespace jj15
{
void test_unordered_set(long& value)
{
	cout << "\ntest_unordered_set().......... \n";

unordered_set<string> c;
char buf[10];

clock_t timeStart = clock();
    for(long i=0; i< value; ++i)
    {
    	try {
    		snprintf(buf, 10, "%d", rand());
        	c.insert(string(buf));
		}
		catch(exception& p) {
			cout << "i=" << i << " " << p.what() << endl;
			abort();
		}
	}
	cout << "milli-seconds : " << (clock()-timeStart) << endl;
	cout << "unordered_set.size()= " << c.size() << endl;
	cout << "unordered_set.max_size()= " << c.max_size() << endl;  //357913941
	cout << "unordered_set.bucket_count()= " << c.bucket_count() << endl;
	cout << "unordered_set.load_factor()= " << c.load_factor() << endl;
	cout << "unordered_set.max_load_factor()= " << c.max_load_factor() << endl;
	cout << "unordered_set.max_bucket_count()= " << c.max_bucket_count() << endl;
  	for (unsigned i=0; i< 20; ++i) {
    	cout << "bucket #" << i << " has " << c.bucket_size(i) << " elements.\n";
  	}			

string target = get_a_target_string();
	{
    timeStart = clock();
auto pItem = find(c.begin(), c.end(), target);	//比 c.find(...) 慢很多
	cout << "std::find(), milli-seconds : " << (clock()-timeStart) << endl;
	if (pItem != c.end())
    	cout << "found, " << *pItem << endl;
  	else
    	cout << "not found! " << endl;
 	}

 	{
    timeStart = clock();
auto pItem = c.find(target);		//比 std::find(...) 快很多
	cout << "c.find(), milli-seconds : " << (clock()-timeStart) << endl;
	if (pItem != c.end())
    	cout << "found, " << *pItem << endl;
  	else
    	cout << "not found! " << endl;
 	}
}
}

使用unorder_map容器

#include <unordered_map>
#include <stdexcept>
#include <string>
#include <cstdlib> //abort()
#include <cstdio>  //snprintf()
#include <iostream>
#include <ctime>
namespace jj16
{
void test_unordered_map(long& value)
{
	cout << "\ntest_unordered_map().......... \n";

unordered_map<long, string> c;
char buf[10];

clock_t timeStart = clock();
    for(long i=0; i< value; ++i)
    {
    	try {
    		snprintf(buf, 10, "%d", rand());
			c[i] = string(buf);
		}
		catch(exception& p) {
			cout << "i=" << i << " " << p.what() << endl;
			abort();
		}
	}
	cout << "milli-seconds : " << (clock()-timeStart) << endl;
	cout << "unordered_map.size()= " << c.size() << endl;	//357913941
	cout << "unordered_map.max_size()= " << c.max_size() << endl;	

long target = get_a_target_long();
    timeStart = clock();
//! auto pItem = find(c.begin(), c.end(), target);	//map 不適用 std::find()
auto pItem = c.find(target);

	cout << "c.find(), milli-seconds : " << (clock()-timeStart) << endl;
	if (pItem != c.end())
    	cout << "found, value=" << (*pItem).second << endl;
  	else
    	cout << "not found! " << endl;
}
}

hash_set/hash_map/hash_multiset/hash_multimap

• 包含gnu C的编译器就可以

• 包含的头文件可能需要修改#include<...>非标准容器，由于时间的原因，没有放在一起,在C++11大会之前就出现了！

• 测试

/*
以下測試 hash_multiset, hash_multimap 過程中遇到阻礙：
headers <hash_set> 和 <hash_map> 各有兩個，
分別在 ...\4.9.2\include\c++\backward 和 ...\4.9.2\include\c++\ext，
不知要用哪一組!
用 <ext\...> 那一組會有問題
   ...\4.9.2\include\c++\backward\hashtable.h
   [Error] no match for call to '(const hasher {aka const __gnu_cxx::hash<std::basic_string<char> >}) (const key_type&)'
用 <backward\...> 那一組有相同的問題.
so, 放棄測試 (no insertion or push_back or ...).
*/

#include <ext\hash_set>
    //...\4.9.2\include\c++\backward\backward_warning.h
	//[Warning] #warning This file includes at least one deprecated or antiquated header
	//which may be removed without further notice at a future date.
	//Please use a non-deprecated interface with equivalent functionality instead.
	//For a listing of replacement headers and interfaces, consult the file backward_warning.h.
	//To disable this warning use -Wno-deprecated. [-Wcpp]

#include <stdexcept>
#include <string>
#include <cstdlib> //abort()
#include <cstdio>  //snprintf()
#include <iostream>
#include <ctime>
namespace jj11
{
void test_hash_multiset(long& value)
{
	cout << "\ntest_hash_multiset().......... \n";

	__gnu_cxx::hash_multiset<string> c;
	char buf[10];

    clock_t timeStart = clock();
    for(long i=0; i< value; ++i)
    {
    	try {
    		snprintf(buf, 10, "%d", rand());
        	//! c.insert(string(buf));
		}
		catch(exception& p) {
			cout << "i=" << i << " " << p.what() << endl;
			abort();
		}
	}
	cout << "milli-seconds : " << (clock()-timeStart) << endl;
}
}
//---------------------------------------------------
#include <ext\hash_map>
    //...\4.9.2\include\c++\backward\backward_warning.h
	//[Warning] #warning This file ... (如上個函數所言)
#include <stdexcept>
#include <string>
#include <cstdlib> //abort()
#include <cstdio>  //snprintf()
#include <iostream>
#include <ctime>
namespace jj12
{
void test_hash_multimap(long& value)
{
	cout << "\ntest_hash_multimap().......... \n";

	__gnu_cxx::hash_multimap<long, string> c;
	char buf[10];

    clock_t timeStart = clock();
    for(long i=0; i< value; ++i)
    {
    	try {
    		snprintf(buf, 10, "%d", rand());
        	//c.insert(...
		}
		catch(exception& p) {
			cout << "i=" << i << " " << p.what() << endl;
			abort();
		}
	}
	cout << "milli-seconds : " << (clock()-timeStart) << endl;		

    timeStart = clock();
    //! auto ite = c.find(...
	cout << "milli-seconds : " << (clock()-timeStart) << endl;
}
}