You can create SolidWorks Addins using SolidWorks API Add-in Templates and Wizards,
e.g. for C# addin
You will have to install the SolidWorks API SDK for this.
If you do not have Visual Studio (also if you do have Visual Studio), you can choose to use AddItIn to create, manage and deploy your SOLIDWORKS macros.
Please visit my website for more info: www.studiozwaard.nl/additin