切片向量 [英] Slicing a vector

问题描述

我有一个std :: vector。我想创建表示该向量切片的迭代器。我该怎么做。在psudo C ++中：

I have a std::vector. I want to create iterators representing a slice of that vector. How do I do it. In psudo C++:

class InterestingType;

void doSomething(slice& s) {
    for (slice::iterator i = s.begin(); i != s.end(); ++i) {
       std::cout << *i << endl;
    }
}
int main() {
   std::vector v();
   for (int i= 0; i < 10; ++i) { v.push_back(i); }
   slice slice1 = slice(v, 1, 5);
   slice slice2 = slice(v, 2, 4);
   doSomething(slice1);
   doSomething(slice2);
   return 0;
}

我不想将元素复制到新的数据结构。 / p>

I would prefer not to have to copy the elements to a new datastructure.

推荐答案

您只需使用一对迭代器：

You'd just use a pair of iterators:

typedef std::vector<int>::iterator vec_iter;

void doSomething(vec_iter first, vec_iter last) {
    for (vec_iter cur = first; cur != last; ++cur) {
       std::cout << *cur << endl;
    }
}

int main() {
   std::vector v();
   for (int i= 0; i < 10; ++i) { v.push_back(i); }

   doSomething(v.begin() + 1, v.begin() + 5);
   doSomething(v.begin() + 2, v.begin() + 4);
   return 0;
}

或者，Boost.Range库应允许您将迭代器对表示为单个对象，但上面是规范的方法来做。

Alternatively, the Boost.Range library should allow you to represent iterator pairs as a single object, but the above is the canonical way to do it.

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