使用Java，如何设置数组以存储下一个索引中的下一个用户输入/

Question

What I'm trying to do is set up 14 arrays that will be of both type string and double to be able to accept input into the first index, and then the next time that the user enters in their information I don't want to add that information into an index that's already been given a value, but I do want to add that new information into the next index of that array. Do I just ++Array[index]? I'm also trying to set up this program to allow the user to be able to access 1 of 3 different IFstatements at a time to input values. If they enter input into an Array in IFstatement1, and then leave IFstatement1, go to IFstatement2 to input something, and then want to come back to IFstatement1 and input data into Arrays there, will the program know to add the newest user inputs into the next index in the array by using the ++Array[index] indicator, or do I have to do something else? How do I accomplish this?

Answer 1

Try looking into the ArrayList object this should work for what you are looking for and it has a nice .add() function to add to the end of the list.

List<String> l1 = new ArrayList<String>();
l1.add("String");
l1.add("Another");

for (String str : l1) {
    System.out.println(str);
}

This will add the strings and provide you the iterator.

If you want another with Doubles just change for or you can have one without generics that will just hold objects <> remove them. Then your for loop would traverse the objects instead.

Answer 2

You can't use ++Array[index] to add an element to an array in Java. As in other statically typed languages, array's are given a size when they are created and can't contain more values then their initial size. So for instance int numbers[10]; can hold 10 integer values. If you want to set the values in that array use something like this:

int numbers[10];
for (int i = 0; i < 10; i++) {
    numbers[i] = 1 + 1;
}

With regards to the user input you describe, you would need to use some form of looping, maybe a while loop?