标准模版库学习之关联式容器

set

/*
目的：学习set容器的使用
*程序输出：
6 5 4 3 2 1
4 already exists
1 2 3 4 5 6
1 element(s) removed
3 4 6
*coll2.erase(coll2.begin(), coll2.find(val));
*当coll2中不存在值等于val的元素时，会返回一个指向结尾的迭代器。
*此时，coll2.erase(coll2.begin(), coll2.find(val));会删除coll2中所有元素。
*/
#include <iostream>
#include <set>
using namespace std;

int main()
{
	typedef set<int, greater<int> > IntSet;  //只是构造时，创建了一个从大到小排列的容器，默认为从小到大。
	// TEMPLATE CLASS set
	/*
	template<class _Kty,
	class _Pr = less<_Kty>,
	class _Alloc = allocator<_Kty> >
	class set
		: public _Tree<_Tset_traits<_Kty, _Pr, _Alloc, false> >
		:*/

	IntSet IntSetcoll;
	IntSetcoll.insert(4);
	IntSetcoll.insert(3);
	IntSetcoll.insert(5);
	IntSetcoll.insert(1);
	IntSetcoll.insert(6);
	IntSetcoll.insert(2);
	IntSetcoll.insert(5);

	set<int> setcoll;	//默认为从小到大。
	setcoll.insert(4);
	setcoll.insert(3);
	setcoll.insert(5);
	setcoll.insert(1);
	setcoll.insert(6);
	setcoll.insert(2);
	setcoll.insert(5);

	IntSet::iterator pos;

	for (pos = IntSetcoll.begin(); pos != IntSetcoll.end(); ++pos)
	{
		cout << *pos << ' ';
	}
	cout << endl;

	pair<IntSet::iterator, bool> status = IntSetcoll.insert(4);
	if (status.second)
	{
		cout << "4 inserted as element "
			<< distance(IntSetcoll.begin(), status.first) + 1 
			<< endl;
	}
	else
	{
		cout << "4 already exists" << endl;
	}

	set<int> coll2(IntSetcoll.begin(), IntSetcoll.end());

	copy(coll2.begin(), coll2.end(), ostream_iterator<int>(cout, " "));
	cout << endl;

	coll2.erase(coll2.begin(), coll2.find(3));

	int num;
	num = coll2.erase(5);
	cout << num << " element(s) removed" << endl;

	copy(coll2.begin(), coll2.end(), ostream_iterator<int>(cout, " "));
	cout << endl;

	getchar();
}

/*
目的：学习set容器的使用(二)
*程序输出：
coll1: 1 2 4 5 6 7
coll2: 7 6 5 4 2 1
coll1: 7 6 5 4 3 2 1
coll1 and coll2 have same sorting criterion
*RuntimeCmp(cmp_mode m = normal) : mode(m)
*不能改为RuntimeCmp() : mode(normal)
*带参数的构造函数，用来在程序运行中构造对象时传递参数
*/
//print.hpp头文件
#include <iostream>

/* PRINT_ELEMENTS()
*- print optional C-string optcstr followed by
*- all elements of the collection coll
*- separated by spaces
*/

template <class T>
inline void PRINT_ELEMENTS (const T& coll, const char* optcstr = "")
{
	typename T::const_iterator pos;

	std::cout << optcstr;
	for (pos = coll.begin(); pos != coll.end(); ++pos)
	{
		std::cout << *pos << ' ';
	}
	std::cout << std::endl;
}

#include <iostream>
#include <set>
//#include "print.hpp"
using namespace std;

template <class T>
class RuntimeCmp
{
public:
	enum cmp_mode {normal, reverse};
private:
	cmp_mode mode;

public:
	RuntimeCmp(cmp_mode m = normal) : mode(m)
	{
	}
	bool operator() (const T &t1, const T &t2) const
	{
		return mode == normal ? t1 < t2 : t2 < t1;
	}
	bool operator== (const RuntimeCmp &rc)
	{
		return mode == rc.mode;
	}
};

typedef set<int, RuntimeCmp<int> > IntSet;              //一个类实例

void fill(IntSet &set);                                                       //stl的函数声明方式

int main()
{
	IntSet coll1;
	fill(coll1);
	PRINT_ELEMENTS(coll1, "coll1: ");

	RuntimeCmp<int> reverse_order(RuntimeCmp<int>::reverse);

	IntSet coll2(reverse_order);
	fill(coll2);
	PRINT_ELEMENTS(coll2, "coll2: ");

	coll1 = coll2;
	coll1.insert(3);
	PRINT_ELEMENTS(coll1, "coll1: ");

	if (coll1.value_comp() == coll2.value_comp())
	{
		cout << "coll1 and coll2 have same sorting criterion" << endl;
	}
	else
	{
		cout << "coll1 and coll2 have different sorting criterion" << endl;
	}
	getchar();
}

void fill(IntSet &set)
{
	set.insert(4);
	set.insert(7);
	set.insert(5);
	set.insert(1);
	set.insert(6);
	set.insert(2);
	set.insert(5);
}

map

/*
目的：学习map容器的使用。本事例运用Maps、Strings并于执行期指定排序准则事例程序
*程序输出：
Bestatter       undertaker
Deutschland     Germany
Haken           snag
Hund            dog
Unternehmen     enterprise
arbeiten        work
deutsch         German
gehen           walk
unternehmen     undertake

arbeiten        work
Bestatter       undertaker
deutsch         German
Deutschland     Germany
gehen           walk
Haken           snag
Hund            dog
Unternehmen     undertake
*/
#include <iostream>
#include <iomanip>
#include <map>
#include <string>
#include <algorithm>
using namespace std;

/* function object to compare strings
* - allows you to set the comparison criterion at runtime
* - allows you to compare case insensitive
*/
class RuntimeStringCmp
{
public:
	enum cmp_mode {normal, nocase};
private:
	const cmp_mode mode;

	static bool nocase_compare(char c1, char c2)
	{
		return toupper(c1) < toupper(c2);
	}

public:
	RuntimeStringCmp(cmp_mode m = normal) : mode(m)
	{
	}

	bool operator() (const string &s1, const string &s2) const
	{
		if (mode == normal)
		{
			return s1 < s2;
		} 
		else
		{
			return lexicographical_compare(s1.begin(), s1.end(), s2.begin(), s2.end(), nocase_compare);
		}
	}
};

/*  container type
* - map with
* - string keys
* - string values
* - the special comparison object type
*/

typedef map<string, string, RuntimeStringCmp> StringStringMap;      

//function that fills and prints such containers
void fillAndPrint(StringStringMap &coll);                                                       //stl的函数声明方式

int main()
{
	//create a container with the default comparison criterion
	StringStringMap coll1;
	fillAndPrint(coll1);

	//create an object
	RuntimeStringCmp ignorecase(RuntimeStringCmp::nocase);

	//create a container
	StringStringMap coll2(ignorecase);
	fillAndPrint(coll2);

	getchar();
}

void fillAndPrint(StringStringMap &coll)
{
	coll["Deutschland"] = "Germany";
	coll["deutsch"] = "German";
	coll["Haken"] = "snag";
	coll["arbeiten"] = "work";
	coll["Hund"] = "dog";
	coll["gehen"] = "go";
	coll["Unternehmen"] = "enterprise";
	coll["unternehmen"] = "undertake";
	coll["gehen"] = "walk";
	coll["Bestatter"] = "undertaker";

	//print
	StringStringMap::iterator pos;
	cout.setf(ios::left, ios::adjustfield);
	for (pos = coll.begin(); pos != coll.end(); ++pos)
	{
		cout <<setw(15) << pos->first.c_str() << " " <<pos->second << endl;
	}
	cout << endl;
}