若要將vector中反過來列印，該怎麼做呢?STL提供了reverse_iterator。
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/*
2
(C) OOMusou 2006 http://oomusou.cnblogs.com
3
4Filename : ReverseIterator.cpp
5Compiler : Visual C++ 8.0 / ISO C++
6Description : Demo how to use reverse_iterator
7Release : 12/17/2006 1.0
8
*/
9
#include <iostream>
10#include <vector>
11#include <algorithm>
12
13using namespace std;
14int main() {
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int ia[] = {1, 2, 3};
16 vector<int> ivec(ia, ia + sizeof(ia) / sizeof(int));
17
18 // use reverse_iterator by for loop
19 for(vector<int>::reverse_iterator r_iter = ivec.rbegin(); r_iter != ivec.rend(); ++r_iter)
20 cout << *r_iter << " ";
21
22 cout << endl;
23
24 // use ordinary iterator to print reversely
25 for(vector<int>::const_iterator iter = (--ivec.end()); iter >= ivec.begin();iter--) {
26 cout << *iter << " ";
27 if (iter == ivec.begin())
28 break;
29
}
30
31 cout << endl;
32
33 // use reverse_iterator with copy() algorithm
34 copy(ivec.rbegin(), ivec.rend(), ostream_iterator<int>(cout, " "));
35 cout << endl;
36}
/* 
2
(C) OOMusou 2006 http://oomusou.cnblogs.com3
4
Filename : ReverseIterator.cpp5
Compiler : Visual C++ 8.0 / ISO C++6
Description : Demo how to use reverse_iterator7
Release : 12/17/2006 1.08
*/9
#include <iostream>10
#include <vector>11
#include <algorithm>12
13
using namespace std;14
int main() {
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int ia[] = {1, 2, 3};
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vector<int> ivec(ia, ia + sizeof(ia) / sizeof(int));17
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// use reverse_iterator by for loop19
for(vector<int>::reverse_iterator r_iter = ivec.rbegin(); r_iter != ivec.rend(); ++r_iter) 20
cout << *r_iter << " ";21
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cout << endl;23
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// use ordinary iterator to print reversely25
for(vector<int>::const_iterator iter = (--ivec.end()); iter >= ivec.begin();iter--) {26
cout << *iter << " ";27
if (iter == ivec.begin()) 28
break;29
}30
31
cout << endl;32
33
// use reverse_iterator with copy() algorithm34
copy(ivec.rbegin(), ivec.rend(), ostream_iterator<int>(cout, " "));35
cout << endl;36
}
執行結果
3 2 13 2 13 2 1請按任意鍵繼續 . . .
19行的for loop，使用了reverse_iterator，讓我們很簡單的如操作一般的iterator般去處理reverse_iterator。
25行到29行，使用了一般的iterator去處理，程式有點詭異，主要是讓我們看出，若沒有reverse_iterator，程式有多難寫。
copy() algorithm也可搭配reverse_iterator，只需一行就可以了。