1. 计算机名称
   GetComputerNameEx:
   https://docs.microsoft.com/en-us/windows/desktop/api/sysinfoapi/nf-sysinfoapi-getcomputernameexa

#include <iostream>  
#include<string>
#include <Windows.h>
#include <iostream>

using namespace std;

int main()
{
    typedef struct _ENUM_NAME
    {
        COMPUTER_NAME_FORMAT eNum;
        LPCTSTR lpName;

    }ENUM_NAME;
#define ENTRY(x) {x,_TEXT(#x)}
    ENUM_NAME arrE[] = {
        ENTRY(ComputerNameNetBIOS),
        ENTRY(ComputerNameDnsHostname),
        ENTRY(ComputerNameDnsDomain),
        ENTRY(ComputerNameDnsFullyQualified),
        ENTRY(ComputerNamePhysicalNetBIOS),
        ENTRY(ComputerNamePhysicalDnsHostname),
        ENTRY(ComputerNamePhysicalDnsDomain),
        ENTRY(ComputerNamePhysicalDnsFullyQualified)
    };


    DWORD dwSize = 0x1000;
    LPTSTR szBuffer = new TCHAR[dwSize];
    for (int i = 0; i < _countof(arrE); i++)
    {
        if (!szBuffer) break;
        memset(szBuffer, 0, dwSize);
        BOOL bRet = GetComputerNameEx(arrE[i].eNum, szBuffer,&dwSize);
        if (bRet) {
            //cout << szBuffer << endl;
        }
        else if (GetLastError() == ERROR_MORE_DATA) {
            delete[]szBuffer;
            szBuffer = NULL;
            szBuffer = new TCHAR[dwSize];
            if (szBuffer) {
                bRet = GetComputerNameEx(arrE[i].eNum, szBuffer, &dwSize);
            }
        }
        if (bRet)
        {
            cout << arrE[i].lpName << "\t\t\t" << szBuffer << endl;
        }
    }
    delete[]szBuffer;
    system("pause");
    return 0;
}

2. 用户名
   GetUserNameEx
   https://docs.microsoft.com/zh-cn/windows/desktop/api/secext/nf-secext-getusernameexa

#include<iostream>
#include<tchar.h>
#include<windows.h>
#include<string>
#include<winerror.h>
#define SECURITY_WIN32
#include<security.h>

#pragma comment(lib,"Secur32.lib")

using namespace std;
int main()
{
    typedef struct _ENUM_NAME
    {
        EXTENDED_NAME_FORMAT eNum;
        LPCTSTR lpName;
    }ENUM_NAME;
#define ENTRY(x) {x,_TEXT(#x)}
    ENUM_NAME arrE[] = {
        //ENTRY(NameUnknown),
        ENTRY(NameFullyQualifiedDN),
        ENTRY(NameSamCompatible),
        ENTRY(NameDisplay),
        ENTRY(NameUniqueId),
        ENTRY(NameCanonical),
        ENTRY(NameUserPrincipal),
        ENTRY(NameCanonicalEx),
        ENTRY(NameServicePrincipal),
        ENTRY(NameDnsDomain),
        ENTRY(NameGivenName),
        ENTRY(NameSurname)
    };


    DWORD dwSize = 0x1000;
    LPTSTR szBuffer = new TCHAR[dwSize];
    for (int i = 0; i < _countof(arrE); i++)
    {
        if (!szBuffer) break;
        memset(szBuffer, 0, dwSize);
        DWORD dwTemp = dwSize;
        BOOL bRet = GetUserNameEx(arrE[i].eNum, szBuffer,&dwTemp);
        if (bRet) {
            //cout << szBuffer << endl;
        }
        else
        {
            DWORD iError = GetLastError();
            if (iError == ERROR_MORE_DATA) {
                delete[]szBuffer;
                szBuffer = NULL;
                dwSize = dwTemp;
                szBuffer = new TCHAR[dwSize];
                if (szBuffer) {
                    bRet = GetUserNameExA(arrE[i].eNum, szBuffer, &dwSize);
                }
            }
            else if (iError == ERROR_NO_SUCH_DOMAIN)
            {
                cout << arrE[i].lpName << "\t\t" << "ERROR_NO_SUCH_DOMAIN" << endl;
            }
            else if (iError == ERROR_NONE_MAPPED)
            {
                cout << arrE[i].lpName << "\t\t" << "ERROR_NO_SUCH_DOMAIN" << endl;
            }
            else {
                cout << iError << endl;
            }
        }
        if (bRet)
        {
            cout << arrE[i].lpName << "\t\t\t" << szBuffer << endl;
        }
    }
    delete[]szBuffer;
    system("pause");
    system("pause");
    return 0;
}

3. 枚举控制面板上列出的用户列表：

#include<iostream>
#include<tchar.h>
#include<windows.h>
#include<string>
#include<winerror.h>
#include<vector>
#include<lm.h>
#pragma comment(lib,"netapi32.lib")

using namespace std;

int GetLocalGroupUsers(vector<wstring> & vecUser)
{
    LOCALGROUP_INFO_0 *pGroups = NULL;
    DWORD dwGroupNum;
    DWORD total;

    NET_API_STATUS nStatus = NetLocalGroupEnum(NULL,
        0,
        (LPBYTE*)&pGroups,
        MAX_PREFERRED_LENGTH,
        &dwGroupNum,
        &total,
        NULL);

    if (nStatus == NERR_Success && pGroups != NULL)
    {
        for (int i = 0; i < dwGroupNum; i++) {

            LOCALGROUP_MEMBERS_INFO_1 *pMembers = NULL;
            DWORD dwMemNum, totalentries;

            nStatus = NetLocalGroupGetMembers(NULL,
                pGroups[i].lgrpi0_name,
                1,
                (LPBYTE*)(&pMembers),
                MAX_PREFERRED_LENGTH,
                &dwMemNum,
                &totalentries,
                NULL);
            if (nStatus == NERR_Success && pMembers)
            {
                for (int iIndex = 0; iIndex < dwMemNum; iIndex++)
                {
                    if (pMembers[iIndex].lgrmi1_sidusage != SID_NAME_USE::SidTypeUser) continue;
                    if (find(vecUser.begin(), vecUser.end(), pMembers[iIndex].lgrmi1_name) == vecUser.end())
                    {
                        vecUser.push_back(pMembers[iIndex].lgrmi1_name);
                    }
                }
                if (pMembers)
                {
                    NetApiBufferFree(pMembers);
                    pMembers = NULL;
                }
            }
            else
            {
                cout << "NetLocalGroupGetMembers fail, Error: " << nStatus << endl;
            }

        }
        if (pGroups)
        {
            NetApiBufferFree(pGroups);
            pGroups = NULL;
        }
    }
    else
    {
        cout << "NetLocalGroupEnum fail, Error: " << nStatus << endl;
    }
    return vecUser.size();
}
void EnumLocalValidUsers(vector<wstring> &localValid)
{
    DWORD dwLevel = 2;
    LPUSER_INFO_2 pBuf = NULL;
    NET_API_STATUS nStatus;

    vector<wstring> arrUser;
    //int nAllNum = GetAllUser(arrUser);
    int nNum = GetLocalGroupUsers(arrUser);
    for (int i = 0; i < nNum; i++)
    {
        nStatus = NetUserGetInfo(NULL, arrUser[i].c_str(), dwLevel, (LPBYTE *)&pBuf);
        if (nStatus == NERR_Success)
        {
            if (pBuf != NULL)
            {
                if (pBuf->usri2_flags & UF_ACCOUNTDISABLE)
                {
                    continue;
                }
                localValid.push_back(arrUser[i]);
                if (pBuf != NULL)
                {
                    NetApiBufferFree(pBuf);
                    pBuf = NULL;
                }
            }
        }
        else
        {
            cout << "NetUserGetInfo fail, Error: " << nStatus << endl;
        }

    }
}

#define SHOW_VEC_STRING(SHOW, x) \
    wcout << SHOW << L":" << endl; \
    for (vector<wstring>::iterator it = x.begin(); it != x.end(); it++) \
    { \
        wcout << *it << endl; \
    }

int main()
{
    _tsetlocale(LC_CTYPE, TEXT(""));
    vector<wstring> vecUsers;
    GetLocalGroupUsers(vecUsers);
    SHOW_VEC_STRING(L"GetLocalGroupUsers",vecUsers);
    vecUsers.clear();
    EnumLocalValidUsers(vecUsers);
    SHOW_VEC_STRING(L"EnumLocalValidUsers",vecUsers);
    system("pause");
    system("pause");
    return 0;
}