jsoncpp数组中多个json嵌套

可以使用JsonCpp库中的Json::Value来处理多个嵌套的JSON对象。

假设我们有一个JSON数组，其中包含多个嵌套的JSON对象：

[
  {
    "name": "John",
    "age": 30,
    "address": {
      "street": "123 Main St",
      "city": "Anytown",
      "state": "CA"
    }
  },
  {
    "name": "Jane",
    "age": 25,
    "address": {
      "street": "456 Oak St",
      "city": "Anycity",
      "state": "NY"
    }
  }
]

我们可以使用JsonCpp库将其解析为一个Json::Value对象，然后使用数组下标和键值对来访问其中的数据：

#include <iostream>
#include <json/json.h>

int main() {
  std::string json_str = R"(
    [
      {
        "name": "John",
        "age": 30,
        "address": {
          "street": "123 Main St",
          "city": "Anytown",
          "state": "CA"
        }
      },
      {
        "name": "Jane",
        "age": 25,
        "address": {
          "street": "456 Oak St",
          "city": "Anycity",
          "state": "NY"
        }
      }
    ]
  )";

  Json::Value root;
  Json::Reader reader;
  bool success = reader.parse(json_str, root);
  if (!success) {
    std::cout << "Failed to parse JSON" << std::endl;
    return 1;
  }

  for (int i = 0; i < root.size(); i++) {
    std::cout << "Person " << i << ":\n";
    std::cout << "  Name: " << root[i]["name"].asString() << std::endl;
    std::cout << "  Age: " << root[i]["age"].asInt() << std::endl;
    std::cout << "  Address:\n";
    std::cout << "    Street: " << root[i]["address"]["street"].asString() << std::endl;
    std::cout << "    City: " << root[i]["address"]["city"].asString() << std::endl;
    std::cout << "    State: " << root[i]["address"]["state"].asString() << std::endl;
  }

  return 0;
}

输出结果为：

Person 0:
  Name: John
  Age: 30
  Address:
    Street: 123 Main St
    City: Anytown
    State: CA
Person 1:
  Name: Jane
  Age: 25
  Address:
    Street: 456 Oak St
    City: Anycity
    State: NY

在上面的代码中，我们首先将JSON字符串解析为Json::Value对象。然后，我们使用Json::Value的size()方法获取数组元素的数量，并使用数组下标访问每个JSON对象。最后，我们使用键值对访问每个JSON对象中的数据。