使用阶乘运算符输出数组

i am new to operator overloading. following is my code i am trying to do operator overloading of ! operator to get an array printed out on my console. I am not getting any error but !data isn't being call when i run the main function. i can't find anything on the internet as there is no operator other then << that is being used for overloading. that too with out<<. but here i can't change my main format so i need to find a way to make it work. can anybody point me in the right direction?i am new to operator overloading. following is