How to create a default view programmatically

use code for creating view as below
public void createListView()
{
    SPSite site = new SPSite("http://servername/testsara");
    SPWeb web = site.OpenWeb();
    SPList list = web.Lists["Tasks"];
 
    SPViewCollection allviews = list.Views;
    string viewName = "Test View";
 
    System.Collections.Specialized.StringCollection viewFields = new System.Collections.Specialized.StringCollection();
    viewFields.Add("Title");
    viewFields.Add("Priority");
 
    string myquery = "0";
    allviews.Add(viewName, viewFields, myquery, 100, true, false);
}

You can also set newly created view as default view

SPView yourView = CurrentList.Views[UserView];
yourView.DefaultView = true;
yourView.Update();