Private Declare Function do_encrypt Lib "AES.dll" (ByVal text As String, ByVal keyz As String) As String

Private Sub Command1_Click()
Text3.text = Str(do_encrypt, Val(Text1.text), Val(Text2.text))
End Sub

Text3.text=do_encrypt(Text1.text,Text2.text)

double _stdcall aesen(string path1, string path2, string path3)
{double time;
     .
     .
     .
    return time;
}

Private Declare Function aesen Lib "example2.dll" (ByVal path1 As String, ByVal path2 As String, ByVal path3 As String) As String

Private Sub Command5_Click()
Text5.text = aesen(Text1.text, Text2.text, Text3.text)
End Sub

#include<iostream>
#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
#include <windows.h>
#include <string.h>
#include <memory.h>
#include <process.h>
#include <tchar.h>
#include <dos.h>
#include <conio.h>
#include <fstream>
#include <string>
# include <bitset>
#include <cstring>
#include <algorithm>
using namespace std;
 
#include <time.h>
 
int _stdcall ss(string de)
{
    int size;
    ifstream myfile456 (de.c_str(), ios::binary);
	myfile456.seekg (0, ios::end);
	size = myfile456.tellg();
	cout << "File size is: " << size << " bytes.\n";
	return (size);
}
 
int main()
{
	ss("c:/p.txt");
	return 0;
}

Private Declare Function ss Lib "testing.dll" (ByVal de As String) As Integer

Private Sub Command1_Click()
Text3.Text = ss(Text2.Text)
End Sub