deque-insert

iterator insert(iterator it,const T& x):双端队列中某一元素前增加一个元素x
返回安插点的位置
源码如下:

....
*pos = x_cpoy;
return  *pos; //pos即为新插入点的位置

////////////////////////////////////////
//     	2018/04/24 7:38:54
//      deque-insert
// 在pos之前插入数据
#include <iostream>
#include <deque>
#include <iterator>
#include <algorithm>

using namespace std;

template<class T>
class Print{
public:
	void operator()(T& t){
		cout << t << " ";
	}
};
//=========================

int main(){
	int ary[5] = { 1, 2, 3, 4, 5 };
	//fill(ary, ary + 5, 1);

	deque<int> d;
	deque<int>::iterator it;
	Print<int> print;
	copy(ary,ary+5,back_inserter(d));
	cout << "deque d:" << endl;
	for_each(d.begin(),d.end(),print);
	cout << endl;

	it = d.begin();
	// insert value "5" at the position "it"
	cout << "d.insert(it,5)" << endl;
	d.insert(it, 5);
	for_each(d.begin(),d.end(),print);
	cout << endl;

	// insert range ary+2 - ary+5 at the position "it"
	it = d.begin() + 5;
	cout << "d.insert(it,ary+2,ary+5)" << endl;
	// it 指向  5 1 2 3 4 5 中的最后一个5，并向其前加入元素
	// ary+2 ~ ary+5, 也就是 3 4 5
	d.insert(it, ary + 2, ary + 5);
	for_each(d.begin(),d.end(),print);
	cout << endl;

	// insert 2 value of "20" at the position "it"
	it = d.end() - 2;
	cout << "d.insert(it,2,20)" << endl;
	d.insert(it, 2, 20);
	for_each(d.begin(),d.end(),print);
	cout << endl;
	return 0;
}

/*
OUTPUT:
	deque d:
	1 2 3 4 5
	d.insert(it,5)
	5 1 2 3 4 5
	d.insert(it,ary+2,ary+5)
	5 1 2 3 4 3 4 5 5
	d.insert(it,2,20)
	5 1 2 3 4 3 4 20 20 5 5
*/