STL MAP复制问题

[gaomingok]

如何将MAP1中的内容复制到MAP2中，MAP1中内容仍然保留？

[xiaopoy]

hmm
纯帮顶

http://blog.csdn.net/bat603/archive/2006/12/23/1456141.aspx

也不知复制的有用没。。

[oliver_wei]

用STL中得COPY函数就可以，而且速度比较快。

[R_hgt]

[Quote=引用 10 楼 oliver_wei 的回复:]
用STL中得COPY函数就可以，而且速度比较快。
[/Quote]

能否说的详细点？

[once_and_again]

对迭代器 的操作，比如 插入，排序会改变容器的内容，

比如 复制，查找，应该不会吧？不然闲着没事.

[Longinc]

学习

[lily604]

纯学习

[lzr4304061988012]

#include <iostream>
#include <map>


using namespace std;


void main()
{
	map<int,int> map1;

	

	map<int,int> map2(map1);
	
}

[太乙]

#include<iostream>

#include<map>
#include<string>
using namespace std;
int main()
{
	map<int,string> m1,m2;
	m1[0]="hello";
	m1[1]="world";
	m2 = m1;
	cout<<m2[1]<<endl;
	
	return EXIT_SUCCESS;
}

如果lz想用什么copy泛型函数，肯定不行，因为map内部的结构不允许！！

[太乙]

因为map是一个双向迭代器，对=进行了重新的定义（重载）

所以通过迭代器来改变元素不大好使！

template<class InIt, class OutIt>
    OutIt copy(InIt first, InIt last, OutIt x);
The template function evaluates *(x + N) = *(first + N)) once for each N in the range [0, last - first), for strictly increasing values of N beginning with the lowest value. It then returns x + N. If x and first designate regions of storage, x must not be in the range [first, last).


如果一定要用的话，得改写一下pair类！

lz可以试试~~

[baihacker]

c1 = c2 Assigns all elements of c2 c1
Operation Effect
c.insert(elem) Inserts a copy of elem and returns the position of the new element and, for maps, whether it succeeded
c.insert(pos,elem) Inserts a copy of elem and returns the position of the new element (pos is used as a hint pointing to where the insert should start the search)
c.insert(beg,end) Inserts a copy of all elements of the range [beg,end)(returns nothing)

[太乙]

[Quote=引用 4 楼 baihacker 的回复:]

c1 = c2 Assigns all elements of c2 c1
Operation Effect
c.insert(elem) Inserts a copy of elem and returns the position of the new element and, for maps, whether it succeeded
c.insert(pos,elem) Inserts a copy of elem and returns the position of the new element (pos is used as a hint pointing to where the insert should start the search)
c.insert(beg,end) Inserts a copy of all elements…
[/Quote]
mm出来行动了？？
呵呵~~~~

[gaomingok]

用结构体作为键和值，原来直接赋值就可以了，谢谢各位了