print 2nd largest number ??

Question

Hi hello everyone

Well i manged to use a build in function i.e array.sort(arrayname) to arrange it in ascending order well coming to my array list ex : {5,6,7,9,7,9,3,9}

In the above example there are multiple high & 2nd high numbers right .. if the list is unique its a no brainer :)  

so how to get 2nd highest number from above example & any permament solution for such cases i.e wen we have duplicate values 

TY