C++ thread array and join respectively

#pragma comment(lib,"rpcrt4.lib")

#include <Windows.h>
#include <rpcdce.h>
#include <iostream>
#include <string>
#include <thread>
#include <vector>

using namespace std;

string getUuid()
{
    RPC_CSTR rpcCstr;
    string uuidValue;
    UUID newUUID;
    UuidCreate(&newUUID);
    UuidToStringA(&newUUID, &rpcCstr);
    uuidValue = (char*)rpcCstr;
    RpcStringFreeA(&rpcCstr);
    return uuidValue;
}

void printVector(const vector<string>& vec)
{
    for (const auto& str : vec)
    {
        cout << str << endl;
    }
    cout << endl << endl;
}

uint32_t num = 0;

void vectorDemo()
{
    vector<vector<string>> vec(10);
    for (int i = 0; i < 10; i++)
    {         
        for (int j = 0; j < 10; j++)
        {
            string tempStr = std::to_string(++num) + ","+getUuid();
            vec[i].push_back(tempStr);
        }
    }

    thread tArr[10];
    for (int i = 0; i < 10; i++)
    {
        tArr[i] = thread(printVector, std::ref(vec.at(i)));
    }

    for (int i = 0; i < 10; i++)
    {
        tArr[i].join();
        cout << "Thread " << i << " finished!" << endl;
    }
}

int main()
{
    vectorDemo();
    cin.get();
}

Though it's not run as expected regularlly,but it will aovid access resource conflicts absolutely.