Explain the error: ISO C ++ prohibits private list declaration without type

Question

I have a class that will process an array of objects of another class that I created earlier (which works fine). The problem occurs when I try to create an object of class List.

This is the title of the list class:

#ifndef personlistH
#define personlistH
#include "Person.h"
#include <iomanip>
#include <iostream>
#define SIZE 10

namespace std {

    class PersonList {
private:
    Person persons[SIZE];
    int arrnum;
    string filename;

public:
    Personlist();
    };
}
#endif

This is the main function:

#include <iostream>
#include "PersonList.h"

using namespace std;

int main() {

PersonList personlist;

return 0;   
}

My compiler error:

error: "27 \ PersonList.h ISO C ++ prohibits declaration of` Personlist 'without type "

I was looking for answers, but since I'm pretty new to C ++, this was a bit confusing and I haven't found a suitable one yet. It would be great if you could explain this error to me.

Answer 1

. Personlist();, Personlist();. , , , , , .

Answer 2

(std), .

//PersonList.h

namespace PersonNamespace 
{
    class PersonList 
    {
        //members here
    };
}

//main.cpp

using namespace PersonNamespace;

, Personlist Personlist

Answer 3

, , ; PersonList() PersonList().

, std; . .