So a[5] in the second line of the above refers to only the sixth element of the array. That's neither the entire array, nor is it in-bounds. Notice that there's only five elements in a. (a[0] is the first element :))
You should pass just the name of the array to the constructor. Note that the size of the array is lost when the constructor receives it.
The line Manager1 Manager(...) says you're creating a new Manager1 called Manager. Perhaps it should be the other way around?