ostream_iterator(cout," ")这句该如何理解
ostream_iterator<int>(cout," ")这句该怎么理解啊
ostream_iterator<int>是个类型，后面直接加（cout," ")到底什么意思啊
------解决思路----------------------
构造函数的参数，语法上相当于有这样的定义：
你就可以用 Foo<char>(1, 1.5); 调用构造函数特定的构造函数。
但这里是cplusplus.com对 ostream_iterator构造函数参数的说明：
ostream_iterator (ostream_type& s, const char_type* delimiter);
含义：
s
A stream object, which is associated to the iterator.
Member type ostream_type is the type of such stream (defined as an alias of basic_ostream<charT,traits>, where charT and trais are the second and third class template parameters).
delimiter
C-string with a sequence of character to be inserted after every insertion.
Note that the iterator keeps a copy of the pointer passed (not the content of the C-string).
------解决思路----------------------
看看下面的代码，也许能帮助你理解
ostream_iterator<int>是个类型，后面直接加（cout," ")到底什么意思啊
------解决思路----------------------
构造函数的参数，语法上相当于有这样的定义：
template<class T>
struct Foo {
Foo(int, double); // 两个，别在意类型
};
你就可以用 Foo<char>(1, 1.5); 调用构造函数特定的构造函数。
但这里是cplusplus.com对 ostream_iterator构造函数参数的说明：
ostream_iterator (ostream_type& s, const char_type* delimiter);
含义：
s
A stream object, which is associated to the iterator.
Member type ostream_type is the type of such stream (defined as an alias of basic_ostream<charT,traits>, where charT and trais are the second and third class template parameters).
delimiter
C-string with a sequence of character to be inserted after every insertion.
Note that the iterator keeps a copy of the pointer passed (not the content of the C-string).
------解决思路----------------------
看看下面的代码，也许能帮助你理解
#include <iostream>
#include <iterator>
#include <vector>
#include <deque>
using namespace std;
template<class InputIt, class OutputIt>
OutputIt my_copy(InputIt first, InputIt last,
OutputIt d_first)
{
while (first != last) {
*d_first++ = *first++;
}
return d_first;
}
int
main(int argc, char *argv[])
{
vector<int> v1;
vector<int>::const_iterator i1;
deque<int> q2;
front_insert_iterator<deque<int> > i2(q2);
ostream_iterator<int> i3(cout," ");
v1.push_back(0);
v1.push_back(1);
v1.push_back(2);
v1.push_back(3);
v1.push_back(4);
v1.push_back(5);
v1.push_back(6);
v1.push_back(7);
v1.push_back(8);
v1.push_back(9);
my_copy(v1.begin(), v1.end(), ostream_iterator<int>(cout," "));
cout << endl;
for (i1 = v1.begin(); i1 != v1.end(); ++i1)
*i2++ = *i1;
for (i1 = v1.begin(); i1 != v1.end(); ++i1)
*i3 = *i1;
cout << endl;
for (i1 = v1.begin(); i1 != v1.end(); ++i1)
*i3++ = *i1;
cout << endl;
my_copy(q2.begin(), q2.end(), i3);
cout << endl;
return 0;
}
/* output
0 1 2 3 4 5 6 7 8 9
0 1 2 3 4 5 6 7 8 9
0 1 2 3 4 5 6 7 8 9
9 8 7 6 5 4 3 2 1 0
*/