c++ - 另一种复制算法

Question

我有两个 vector 。

vector<Object> objects;
vector<string> names;

这两个 vector 被填充并且具有相同的大小。我需要一些算法来对对象变量进行赋值。它可能正在使用 boost::lambda。比方说:

some_algoritm(objects.begin(), objects.end(), names.begin(), bind(&Object::Name, _1) = _2);

有什么建议吗？

Answer 1

我认为您需要 std::for_each 因为每个 Object 实例都被就地修改:

std::vector<std::string>::const_iterator names_it = static_cast<const std::vector<std::string>&>(names).begin();

std::for_each(objects.begin(), objects.end(),
              boost::lambda::bind(&Object::Name, boost::lambda::_1) = *boost::lambda::var(names_it)++);

这是一个完整的、可编译的示例:

#include <algorithm>
#include <cstdlib>
#include <iostream>
#include <string>
#include <vector>
#include <boost/lambda/bind.hpp>
#include <boost/lambda/lambda.hpp>

class Object
{
public:
    std::string Name;

    Object(const std::string& Name_ = "")
        : Name(Name_)
    {
    }
};

int main()
{
    std::vector<Object> objects(3, Object());
    std::vector<std::string> names;
    names.push_back("Alpha");
    names.push_back("Beta");
    names.push_back("Gamma");
    std::vector<std::string>::const_iterator names_it = static_cast<const std::vector<std::string>&>(names).begin();

    std::for_each(objects.begin(), objects.end(), boost::lambda::bind(&Object::Name, boost::lambda::_1) = *boost::lambda::var(names_it)++);

    std::vector<Object>::iterator it, end = objects.end();
    for (it = objects.begin(); it != end; ++it) {
        std::cout << it->Name << std::endl;
    }

    return EXIT_SUCCESS;
}

输出:

AlphaBetaGamma