Hello, a Yahoo email address would something like this: firstname.lastname@example.org
If you are referring to the Yahoo email address you used to create your CCM account, you can see that by going into your profile. I can see it, however I will not disclose that information publicly.
However if you have since created a new yahoo email account, then you will have also had to have created a personalised email address. Therefore we can't tell you what your yahoo email address is, only you can do that...
However, if you remember it, and need help recovering your Yahoo account, follow the steps in this article.