C++/JSON 只允许一个顶级项目答案

【问题标题】：C++/JSON Only one top level item allowedC++/JSON 只允许一个顶级项目
【发布时间】：2020-03-30 13:20:28
【问题描述】：

好像我写错了我的对象，但我看过很多例子，我仍然遇到同样的问题。我做 Staff + StaffID 的原因是我可以在有意义的情况下引用该对象。 json 对象的详细信息取决于用户输入的内容

我正在使用 nlohmann/json.hpp 库

    staff = {"Staff " + staffID, {
        {"First Name", first_name},
        {"Last Name", last_name},
        {"Age", age},
        {"StaffID", staffID},
        {"Phone", staff_phone},
        {"Skill 1", skill_1},
        {"Skill 2", skill_2},
        {"Skill 3", skill_3}
    } };

myFile << setw(4) << staff << endl;
myFile.close();

我的 json 文件中的结果，顶部条目还可以：

[
    "Staff 1",
    {
        "Age": 44,
        "First Name": "John",
        "Last Name": "Smith",
        "Phone": "97345345",
        "Skill 1": "Dogs",
        "Skill 2": "Vet",
        "Skill 3": "Grooming",
        "StaffID": "1"
    }
]
[
    "Staff 2",
    {
        "Age": 38,
        "First Name": "Jane",
        "Last Name": "Smith",
        "Phone": "9835735",
        "Skill 1": "Cats",
        "Skill 2": "Surgery",
        "Skill 3": "Grooming",
        "StaffID": "2"
    }
]

更新：更多详情 该函数在一个类中，当用户选择类中的 add_info_staff 函数时，该函数在一个允许用户添加员工的菜单的 while 循环内被调用。

class infoStaff
{
protected:


    json staff;
    char first_name[50];
    char last_name[50];
    int age;
    string staffID;
    string staff_phone;
    string skill_1;
    string skill_2;
    string skill_3;




public:
    void add_info_staff(void)
    {

        ofstream myFile("staff_j.json", ios::app);


        cout << "Please enter the first name:  " << endl;
        cin >> first_name;

        cout << "Please enter the last name:  " << endl;
        cin >> last_name;

        cout << "Please enter the age:  " << endl;
        cin >> age;

        cout << "Please enter the staff ID:  " << endl;
        cin >> staffID;

        cout << "Please enter the staff's phone number:  " << endl;
        cin >> staff_phone;

        cout << "Please enter skill 1 :  " << endl;
        cin >> skill_1;

        cout << "Please enter skill 2 :  " << endl;
        cin >> skill_2;

        cout << "Please enter skill 3 :  " << endl;
        cin >> skill_3;

        staff = {"Staff " + staffID, {
            {"First Name", first_name},
            {"Last Name", last_name},
            {"Age", age},
            {"StaffID", staffID},
            {"Phone", staff_phone},
            {"Skill 1", skill_1},
            {"Skill 2", skill_2},
            {"Skill 3", skill_3}
        } };

    myFile << setw(4) << staff << endl;
    myFile.close();

    }
};

【问题讨论】：

预期结果是["Staff 1" , {...}, "Staff 2", {...}]吗？如果是这样，您将不得不展示更多的程序（接受用户输入、转换为 JSON 并将其写入文件的循环）
如果对 Botje 有帮助，我会添加更多详细信息 :) 无论哪种方式都非常感谢
谢谢谢夫！可能需要查看数组:)

标签： c++ json object

【解决方案1】：

您不能简单地将多个数组输出到一个文件并期望它是一个有效的 JSON 文档。例如，一个 JSON 文档必须有一个顶级值

[
[
    "Staff 1",
    {
        "Age": 44,
        "First Name": "John",
        "Last Name": "Smith",
        "Phone": "97345345",
        "Skill 1": "Dogs",
        "Skill 2": "Vet",
        "Skill 3": "Grooming",
        "StaffID": "1"
    }
],
[
    "Staff 2",
    {
        "Age": 38,
        "First Name": "Jane",
        "Last Name": "Smith",
        "Phone": "9835735",
        "Skill 1": "Cats",
        "Skill 2": "Surgery",
        "Skill 3": "Grooming",
        "StaffID": "2"
    }
]
]

会是正确的，因为您现在在顶层有一个数组。

我无法告诉你你真正追求的是什么，但你需要想出这样的结构并相应地使用 API。

【讨论】：