Dynamic Arrays

I have an array question. I want to use a dynamic array but I don't know how to do this. What I want to do is this, I want to write a form script that takes the elements of the form and submits them in the array then I want to do a loop and check to see if each element in the array has a value and then if it does bullocks for them, but if it doesn't then I want it to come to a screeching halt and tell them what dolts they are for missing a field. So basically I want to have a Required field option for the form. I'm still learning arrays and dynamic arrays are just throwing me and I can't find a good code example to work from. TIA.