Add script reference dynamically through code in SharePoint

To add script reference dynamically follow below stes:

Step-1:
Open visual Studio 2010, Click on File -> New project. Then from the New Project dialog box, Select Visual C# -> SharePoint -> 2010.
Then from the list of SharePoint 2010 project templates select Empty SharePoint Project. Give a name and make sure .net Framework 3.5 is selected as shown in the figure below:

Step-2:
In the next step Give a local site for debugging and Select Deploy as farm solution and click on Finish as shown in the figure below:

Step-3:
Now Right click on the project -> Add -> New Item

Then from the list of installed templates Select Web Part, Give a name and click on Add as shown in the figure below:

Step-4:
Now open the [web part name].cs file and add the below method:

 protected override void OnPreRender(EventArgs e)
        {
            ScriptLink.Register(this.Page, "jQuery/jquery-min-1.6.js", false);
            base.OnPreRender(e);
        }