您如何在Java中创建数学序列？

Question

I want to declare integers, while the program is running.

I run the program, and then I give it via System.in.println an integer and repeat this as long as I want.

I want the program to give those integers a name of a certain type for, for example a(i) or a[i] , dunno, (it should be handy) and then a(i) represents the the i 'th integer I gave the program.
My idea is then that I can use those elements by their name just like, if I had declared them in the first place.
For example add two integers together.
For example I defined a method add+, which waits for 2 integer and then adds them.
For example I write:

add

a(2)

a(47) 

(then I would get here the result.)

I don't think implementing the add function is difficult. However I don't know, how to let the program count the number of inputs or how to let it declare and use variables.

Answer 1

First: Welcome to programming java; it will be a long road.

Here are some hints:

1. Use a List<Integer> to hold the sequence of numbers entered by the user.
2. Actually instanciate a concreate List class, for example LinkedList<Integer>'. If you need to access the elements by index, use an LinkedList<Integer>'. If you need to access the elements by index, use an ArrayList`.\\
3. Each time the user enters a number, create a new Integer and userList.add(newInteger);

Simple sample

List<Integer> userList = new LinkedList<Integer>();

for (index = 0; index < 9; ++index)
{
    Integer newInteger = new Integer(index);

    userList.add(newInteger);
}

for (Integer current : userList)
{
     System.out.println(current);
}

Answer 2

Yeah, I am following the conversation. I am just a bit frustrated, because I can't really write any interesting or practical java programs (yet), because my knowledge isn't that big yet. First I tried to find out, if there was a way to add elements to array, because arrays seemed to me very useful, because each element of an array already has an address. I googled, and it seems that is not possible. I might be able to use the idea with the list, but it seems to be that the length of the list has to have a limit and actually I wanted to avoid that.