Managed C++/CLI

Google Translate:

the function of the program is to remove the same character so that the character appears only once by using recursive

my program is not perfect

#include <iostream>
#include <windows.h>
using namespace std;

int main(){

 char nama[1000];
 int index[100];
 cout<<"masukkan nama = ";												

 for(int i=0; i<strlen(nama); i++){
 	
  int n=0;
  
  for(int j=0; j<strlen(nama); j++){
  	
   if(nama[i] == nama[j]){
   	
   n++;
   
    index[j]=i;
   } 
  }
 }

 for(int i=0; i<strlen(nama); i++){
 	
  if(i == index[i]){
  	
   cout<<nama[i];
  }
 }
}

Form1-MdiContainer()
private: System::Void button1_Click(System::Object^  sender, System::EventArgs^  e) {
    Form2^ MyStForm = Form2::GetForm(true, this);
    MyStForm->MdiParent = this;
    MyStForm->FormBorderStyle = System::Windows::Forms::FormBorderStyle::None;
    MyStForm->Dock = DockStyle::Fill;
    MyStForm->Show();
}
Form2-Top side
    public ref class Form2 : public System::Windows::Forms::Form
    {
        public: static Form2^ Form2::_instance = nullptr;
        public: static Form2^ Form2::GetForm(bool IsMDIChild, System::Windows::Forms::Form^ MyInstFrm) {
            if (_instance == nullptr)
                _instance = gcnew Form2();
            if (_instance->IsDisposed)
                _instance = gcnew Form2();
            if (IsMDIChild)
                _instance->MdiParent = MyInstFrm;
            return _instance;
        }
        blah..blah...blah...
         }

Form2-Load()
private: System::Void Form2_Load(System::Object^  sender, System::EventArgs^  e) {
    String^ MyStrConn = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" + MyExcelFile + "; Extended Properties=\"Excel 12.0; HDR=YES; OLE DB Services=-1; \"";
    String^ MyExcelFile="C:\Students\Names.xlsx";
    String^ MyExcelSheet = "[Sheet1$]";
    String^ MySQLSelect = "select * from " + MyExcelSheet;
    System::Data::OleDb::OleDbConnection^ Cn1 = nullptr;
    Cn1 = gcnew System::Data::OleDb::OleDbConnection();
    Cn1->ConnectionString = MyStrConn;
    System::Data::OleDb::OleDbCommand^ MyCmd = nullptr;
    MyCmd = gcnew System::Data::OleDb::OleDbCommand();
    MyCmd->CommandText = MySQLSelect;
    MyCmd->Connection = Cn1;
    Cn1->Open();
        System::Data::OleDb::OleDbDataAdapter^ Da1 = gcnew System::Data::OleDb::OleDbDataAdapter(MyCmd);
        Da1->Fill(MyDataTable);
    Cn1->Close(); //????????????????? getting stuck
    if (Cn1 != nullptr){
        MyCmd->Cancel();
    }
    //Cn1->ConnectionString = nullptr;
    //Cn1->ReleaseObjectPool();
    MyCmd = nullptr;
    Cn1 = nullptr;

} 

#include <cmath>
#include <stdio.h>

int main(int, char**) 
{
    return std::abs(INT_MIN);
}

#pragma once

namespace CppTutorial {

	using namespace System;
  using namespace System::Threading::Tasks;

	/// <summary>
	/// Summary for MainForm
	/// </summary>
	public ref class MainForm : public System::Windows::Forms::Form
	{
	public:
		MainForm(void)
		{
			InitializeComponent();
			//
			//TODO: Add the constructor code here
			//
		}

	protected:
		/// <summary>
		/// Clean up any resources being used.
		/// </summary>
		~MainForm()
		{
			if (components)
			{
				delete components;
			}
		}

	private:
		/// <summary>
		/// Required designer variable.
		/// </summary>
		System::ComponentModel::Container ^components;

#pragma region Windows Form Designer generated code
		/// <summary>
		/// Required method for Designer support - do not modify
		/// the contents of this method with the code editor.
		/// </summary>
		void InitializeComponent(void)
		{
      this->SuspendLayout();
      // 
      // MainForm
      // 
      this->AutoScaleDimensions=System::Drawing::SizeF(6,13);
      this->AutoScaleMode=System::Windows::Forms::AutoScaleMode::Font;
      this->ClientSize=System::Drawing::Size(284,261);
      this->Name=L"MainForm";
      this->Text=L"MainForm";
      this->Shown+=gcnew System::EventHandler(this,&MainForm::MainForm_Shown);
      this->ResumeLayout(false);

    }
#pragma endregion

  public:
  
  static void Body(int index)
  {
    int test=0;
  }

  delegate void MyDelegate(int index);

  System::Void MainForm_Shown(System::Object^ sender,System::EventArgs^ e) 
  {
    MyDelegate ^body=gcnew MyDelegate(MainForm::Body);     
    ParallelLoopResult ^result=Parallel::For(0,10,(System::Action <int> ^)body);
  }

  };
}

DataTable ^dt = gcnew DataTable();
					 
					 dt->Columns->Add("Name");
					 dt->Columns->Add("Surname");
					 dt->Columns->Add("Address");
					 dt->Columns->Add("Phone");

					 DataRow^ datarow = dt->NewRow();
					 					 
					 datarow["Name"] = <pre lang="C++">

I want to write a C++/CLI wrapper class library which can be utilized in both C++ and C# applications. Step by step procedure will be more helpful along with project configurations.Basically i want to consume the c++/cli dll in both the applications. i need to write a wrapper which will be compatible with both the applications 

class Pojazd
{
public:

    virtual void buduj()=0;
};

class Sedan : Pojazd
{
private:
    string typ="Sedan";
public:
    string marka;
    string model;
    int hp;//horse power
    double v;//pojemnosc silnika
    int cena;
    virtual void buduj()
    {
        cout << marka << " " << model << " " << endl;
        cout << "Typ nadwozia: " << typ << endl;
        cout << "Dane Techniczne: " << endl;
        cout << "-" << hp << " KM" << "\n-Silnik: " << v << "L" << endl;
        cout << "Cena " << cena << "\nmiesieczna rata " << cena / 12 << endl;
    }
    Sedan(string nadwozie)
    {
        nadwozie = typ;
    }

};

class Hatchback : Pojazd
{

    string typ;
public:
    string marka;                                             
    string model;
    int hp;//horse power
    double v;//pojemnosc silnika
    int cena;
    virtual void buduj()
    {
        cout << marka << " " << model << " " << endl;
        cout << "Typ nadwozia: " << typ << endl;
        cout << "Dane Techniczne: " << endl;
        cout << "-" << hp << " KM" << "\n-Silnik: " << v << "L" << endl;
        cout << "Cena " << cena << "\nmiesieczna rata " << cena / 12 << endl;
    }
    Hatchback(string typ)
    {
        typ = typ;
    }
};

int main()
{
    w:
    int switch_on;
    cout << "1.Sedan\n2.Hatchback"<<endl;
    cin >> switch_on;
    switch (switch_on)
    {
    case 1:
    {
        cout << "1.Mercedes\n2.BMW\n3.Audi\n";
        cin >> switch_on;
        switch (switch_on)
        {
        case 1:
        {
            Sedan Mercedes("Sedan");
            Mercedes.marka = "Mercedes";
            Mercedes.model = "A klasa";
            Mercedes.hp = 145;
            Mercedes.v = 2.1;
            Mercedes.cena = 156000;

            Sedan* wsk_sedan;
            wsk_sedan = &Mercedes;
            wsk_sedan->buduj();

        }
        case 2:
        {
            Sedan BMW("Sedan");
            BMW.marka = "BMW";
            BMW.model = "d531i";
            BMW.hp = 166;
            BMW.v = 2.5;
            BMW.cena = 188770;

            Sedan* wsk_sedan;
            wsk_sedan = &BMW;
            wsk_sedan->buduj();
        }
         
        }
    
}
        break;
    case 2:
    {
        
    }
        break;
    }
    

   
    

    return 0;
}