Object Disposal best practice

If we are not performing any operations on the SPSite object, we can write as in the following code example.

void CombiningCallsBestPractice()
{
    using (SPSite siteCollection = new SPSite(SPContext.Current.Web.Url))
    using (SPWeb web = siteCollection.OpenWeb())
        {
        //Perform operations on site.
        } // SPWeb object web.Dispose() automatically called; SPSite object
          // siteCollection.Dispose() automatically called.
}