迭代向量中的向量

Question

我正在尝试迭代这个向量，以确定我的一个检查向量中名称的函数是否有效。

  typedef struct device_t
    {
        string id;
        vector<string> capabilities;
    } Device;


vector<Device> devices = {
  { .id = "Television", .capabilities = { "audio", "channel" } },
  { .id = "Smart thermostat", .capabilities = { "temperature" } },
  { .id = "Stereo system", .capabilities = { "audio", "music" } },
  { .id = "Kitchen sink", .capabilities = { } },
  { .id = "Paper shredder", .capabilities = { "shredding" } }
};

 vector<Device>::iterator it;

    for (it = devicecheck.begin(); it != devicecheck.end(); it++) {
        std::cout<< *it;
    }

然而，我不知道如何到达矢量devices中的{.id}部分。有什么建议吗？

Answer 1

it->capabilities是当前迭代器it指向的Device的std::vector<std::string> capabilities。要在capabilities上迭代，您可以这样做：

for (it = devicecheck.begin(); it != devicecheck.end(); it++) {
    for (auto it2 = it->capabilities.begin(); it2 != it->capabilities.end(); it2++)
    {
        std::cout << *it2 << " "; 
    }
}

如果您不一定需要访问迭代器本身(而只需要访问底层对象)，请考虑基于范围的for循环语法：

for (auto& device : devicecheck)
{
    for (auto& capability : device.capabilities)
    {
        std::cout << capability << " ";
    }
}