Create wiki page programatically
This example creates wiki page on site collection created from Enterprise wiki template
Add reference to Microsoft.SharePoint.Publishing
SPWeb web = SPContext.Current.Web;
string tit = "My code article 3";
string articleTitle = string.Format("{0}.aspx", tit);
PublishingWeb pWeb = PublishingWeb.GetPublishingWeb(web);
SPQuery query = new SPQuery();
query.Query = string.Format("<Where><Eq><FieldRef Name='FileLeafRef' /><Value Type='Text'>{0}</Value></Eq></Where>", articleTitle);
query.RowLimit = 1;
PublishingPageCollection pages = pWeb.GetPublishingPages(query);
if (pages.Count == 0)
{
PublishingPage page = pWeb.AddPublishingPage(articleTitle, pWeb.DefaultPageLayout); //EnterpriseWiki.aspx is default page layout for wiki site collection
page.Update();
page.ListItem["PublishingPageContent"] = "<h1>My content</h1>And more.";
page.Update();
}