nlohmann / json store std::Array

I am executing following code, Observed that values in json are getting stored as there ASCII codes. for a single char and char array, we can convert it to string and store as it is, but not able to find a way for unsigned char. please find the code sample below:

#include "stdafx.h"
#include <iostream>
#include <string>
#include <array>
#include <initializer_list>

#include "nlohmann/json.hpp"
using nlohmann::json;

std::vector<char> CharArrayToVector(std::array<char, 10> number)
{
    std::vector<char> vec;

    for (const auto &c : number)
    {
        if (c != '\0')
            vec.push_back(c);
    }
    std::cout << "Element stored in char vector are" << std::endl;
    for (const auto &c : vec)
    {
        std::cout << c << ",";

    }
    std::cout << std::endl;
    return vec;
}

std::vector<unsigned char> UnsignedCharArrayToVector(std::array<unsigned char, 10> number)
{
    std::vector<unsigned char> vec;
    for (const auto &c : number)
    {
        if (c != '\0')
            vec.push_back(c);
    }
    std::cout << "Element stored in unsigned char vector are" << std::endl;
    for (const auto &c : vec)
    {
        std::cout << c << ",";
    }
    std::cout << std::endl;
    return vec;
}

class One
{
public:
    One(std::array<char, 10> firstName, const char a, std::array<unsigned char, 10> lastName) :
        m_firstName(firstName), m_A(a), m_lastName(lastName)
    {
    }
    std::array<char, 10> FirstName()
    {
        return m_firstName;
    }
    char A()
    {
        return m_A;
    }
    std::array<unsigned char, 10> LastName()
    {
        return m_lastName;
    }

private:
    std::array<char, 10> m_firstName;
    char m_A;
    std::array<unsigned char, 10> m_lastName;
};

std::string ToJsonString(One &one)
{
    nlohmann::json j =
    {
        { "FirstName", CharArrayToVector(one.FirstName()) },
        { "A", std::string(1, one.A()) },
        { "LastName", UnsignedCharArrayToVector(one.LastName()) }
    };

    std::cout << j.dump(4) << std::endl;
    std::string str = j.dump(4);
    return str;
}

void ToObjectsOne(std::string json)
{
    nlohmann::json data;
    try
    {
        data = nlohmann::json::parse(json);
    }
    catch (nlohmann::json::exception& exception)
    {
        std::cerr << "EPS: Failed to parse line[" << json << "]";
        std::cerr << "EPS: Exception[" << exception.what() << "]";
    }

    std::cout << " +++++++" << std::endl;
    std::vector<char> vec1 = data["FirstName"].get<std::vector<char>>();
    std::cout << "A: " << (data["A"].get<std::string>()) << std::endl;
    std::vector<unsigned char> vec2 = data["LastName"].get<std::vector<unsigned char>>();

    std::cout << "Element after deserialization in char vector are" << std::endl;
    for (const auto &c : vec1)
    {
        std::cout << c << ",";
    }
    std::cout << std::endl;

    std::cout << "Element after deserialization in unsigned char vector are" << std::endl;
    for (const auto &c : vec2)
    {
        std::cout << c << ",";
    }
    std::cout << std::endl;
}


int main()
{
    One one({ 'A', 'B', 'C', 'D' }, 'A', { '1', '2', 'A', 'B', 'C' });
    std::string jsonStr = ToJsonString(one);
    ToObjectsOne(jsonStr);
    return 0;
}  

I am getting following output for this:

Element stored in char vector are
A,B,C,D,
Element stored in unsigned char vector are
1,2,A,B,C,
{
    "A": "A",
    "FirstName": [
        65,
        66,
        67,
        68
    ],
    "LastName": [
        49,
        50,
        65,
        66,
        67
    ]
}
 +++++++
A: A
Element after deserialization in char vector are
A,B,C,D,
Element after deserialization in unsigned char vector are
1,2,A,B,C,