C++ – Adding C++ function to VBA/Excel

C++ – Adding C++ function to VBA/Excel

Posted on April 24, 2017 by Vitosh Posted in C++, VBA \ Excel

After adding a c# library to VBA I have decided to take a look how to do a similar trick with C++.

 

C++ is a bit fancier in a way. And it works somehow else. So, let’s start. Imagine that we want to calculate the sum of all the numbers between 0 and n. The easiest way to do it (without thinking) is to take all the numbers and to sum them up. In C++ this formula would look like this:

 

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int __stdcall SimpleSlowMath(int & x) { int result = 0; for (int a = 0; a <= x; a++) { result += a; } return result; }

Thus, in order to export this “beauty” to Excel with Visual Studio, we should do the following:

First create a new DLL project (Win32 Project) with VS.

 

Then select a DLL project and then check “Empty project”

 

Once in the empty project we need 2 files – a *.cpp file and a *.def file.

 

In the *.def file we write the following:

 

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LIBRARY "VitoshAcademy" EXPORTS SimpleSlowMath

Before compiling, we go to Properties of the project>Linker>Input>Module Definition File and we write the name of the def file.

 

Compile the project with F6. And than go to VBA and have fun:

 

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Declare Function SimpleSlowMath Lib "C:\Documents\Visual Studio 2015\Projects\SSMath\Debug\SSMath.dll" (ByRef x As Long) As Long                              Sub TestMe()          Dim n As Long: n = 321          Debug.Print SimpleSlowMath(n)     Debug.Print SimpleSlowMathVBA(n)     Debug.Print SimpleQuickMathVBA(n)   End Sub   Public Function SimpleSlowMathVBA(x As Long) As Long       Dim result  As Long: result = 0     Dim counter As Long          For counter = 0 To x Step 1         result = result + counter     Next counter          SimpleSlowMathVBA = result   End Function   Public Function SimpleQuickMathVBA(x As Long) As Long       SimpleQuickMathVBA = (x * (x + 1)) / 2   End Function

The TestMe Sub routine now works! Taking the formula from the SSMath.dll, as we have written it in C++. Super