Add a New Item in SharePoint List using C#

// Open your SPSite
using(SPSite oSite = new SPSite("http://ils-jacobr:35526")) {
    //Get a Root Web
    using(SPWeb oWeb = oSite.RootWeb) {
        //Get a Particular List
        SPList oList = oWeb.Lists["EmployeeDetails"];
        //Add a New item
        SPListItem oSPListItem = oList.Items.Add();
        oSPListItem["Employee ID"] = txtEmployeeId.Text;
        oSPListItem["City"] = txtCity.Text;
        oSPListItem["State"] = txtState.Text;
        oSPListItem["First Name"] = txtFirstName.Text;
        oSPListItem["Last Name"] = txtLastName.Text;
        oSPListItem.Update();
    }
}