string类型的字符串转json

可以使用第三方库，如jsoncpp或者rapidjson来将string类型的字符串转换为json格式。以下是使用jsoncpp的示例代码：

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

int main() {
    std::string str = "{\"name\":\"John\",\"age\":30,\"city\":\"New York\"}";
    Json::Value root;
    Json::CharReaderBuilder builder;
    Json::CharReader* reader = builder.newCharReader();
    std::string errors;
    bool parsingSuccessful = reader->parse(str.c_str(), str.c_str() + str.size(), &root, &errors);
    delete reader;
    if (parsingSuccessful) {
        std::cout << "Name: " << root["name"].asString() << std::endl;
        std::cout << "Age: " << root["age"].asInt() << std::endl;
        std::cout << "City: " << root["city"].asString() << std::endl;
    } else {
        std::cout << "Parsing error: " << errors << std::endl;
    }
    return 0;
}