chapter9-39.cpp

C++STL程序员开发指南

//文件名:CHAPTER9-39.cpp
#pragma warning(disable: 4786)
#include <set>
#include <iostream>
int main()
{
	std::set<int> c1 ;
	int ai[] = {0, 1, 2, 3} ;
	//construct from a range
	std::set<int> c2(ai, ai + 4) ;
	//copy constructor
	std::set<int> c3(c2) ;
	std::set<int>::iterator Iter ;
	std::set<int>::reverse_iterator RevIter ;
	//判断c1是否为空
	if(c1.empty())
	{		std::cout << "set c1 is empty" << std::endl ;	}
	else
	{		std::cout << "set c1 is not empty" << std::endl ;	}
	//使用begin, end显示c2所有元素
	std::cout << "c2 (using begin, end)  = " ;
	for(Iter = c2.begin(); Iter != c2.end(); Iter++)
	{		std::cout << *Iter << " " ;	}
	std::cout << std::endl ;
	//使用rbegin,rend显示c2所有元素
	std::cout << "c2 (using rbegin, rend) = " ;
	for(RevIter = c2.rbegin(); RevIter != c2.rend(); RevIter++)
	{		std::cout << *RevIter << " " ;	}
	std::cout << std::endl ;
	//使用insert向c1插入元素
	c1.insert(ai, ai+4) ;
	std::pair<std::set<int>::iterator, bool> pr ;
	pr = c1.insert(0) ;
	if(pr.second == true)
	{		std::cout << "element 0 was inserted in c1 successfully" << std::endl ;	}
	else
	{
		std::cout << "element 0 already exists in c1 and *(pr.first) = " 
			<< *(pr.first) << std::endl ;
	}
	//使用find进行元素的查找
	std::set<int>::const_iterator constIter = c1.find(3) ;
	if(constIter != c1.end())
	{		std::cout << "c1 contains element 3, *constIter = " 
			<< *constIter << std::endl ;
	}
	//使用max_size返回c1的最大元素大小
	std::cout << "c1.max_size() = " << c1.max_size() << std::endl ;
	//使用size返回c1的最大元素大小
	std::cout << "c1.size() = " << c1.size() << std::endl ;
	//使用swap把c1和c2进行元素交换
	c1.insert(4) ;
	c2.swap(c1) ;
	std::cout << "The last element of c2 = " << *(c2.rbegin())
		<< std::endl ;
	//使用clear进行c1元素的清除
	c1.clear() ;
	std::cout << "After calling c1.clear(), c1.size() = " 
		<< c1.size() << std::endl ;
	//使用get_allocator获取c1的内存分配器
	std::set<int>::allocator_type a1 = c1.get_allocator() ;
	//使用key_compare进行c1的键值检验
	std::set<int>::key_compare kc = c2.key_comp() ;
	bool result = kc(2, 3) ;
	if(result == true)
	{		std::cout << "kc is function object used by c2.  kc(2,3) = true" << std::endl ;	}
	else
	{		std::cout << "kc is function object used by c2.  kc(2,3) = false" << std::endl ;	}
	//使用value_comp进行c2的键值检验
	std::set<int>::value_compare vc = c2.value_comp() ;
	result = vc(10, 4) ;
	if(result == true)
	{		std::cout << "vc is function object used by c2.  vc(10,4) = true" << std::endl ;	}
	else
	{		std::cout << "vc is function object used by c2.  vc(10,4) = false" << std::endl ;	}
	//使用upper_bound返回c2当前值的最近增值迭代器
	std::cout << "* (c2.upper_bound(3)) = " 
		<< *(c2.upper_bound(3)) << std::endl ;
	//使用lower_bound返回c2当前值的最近降值迭代器
	std::cout << "* (c2.lower_bound(3)) = " 
		<< *(c2.lower_bound(3)) << std::endl ;
	//使用equal_range返回当前元素的上下两个迭代器
	std::pair<std::set<int>::const_iterator, std::set<int>::const_iterator> pr1 = c2.equal_range(3) ;
	std::cout << "*(pr1.first) = " << *(pr1.first) << "\t" 
		<< "*(pr1.second) = " << *(pr1.second) << std::endl ;
	//使用erase进行元素的删除操作
	if(c3.erase(1) != 0)
	{		std::cout << "c3 does not contain 1 any more" << std::endl ;	}
	else
	{		std::cout << "No elements in c3 match key 1" << std::endl ;	}
	if((c2.erase(c2.begin())) != c2.end())
	{		std::cout << "c2 does not contain 0 any more" << std::endl ;	}
	else
	{		std::cout << "No elements in c2 match key 0" << std::endl ;	}
	c3.erase(c3.begin(), c3.end()) ;
	std::cout << "after c3.erase(c3.begin(), c3.end()), c3.size() = " 
		<< c3.size() << std::endl ;
	return 0 ;
}