Need help with arrays

[B0nk_]

Hello, I could really use someones help on this... I have to create a program where a user can infinity enter values (so not a static array) and then when send user is done entering arrays  it adds, averages, etc... the problem i cant figure out to to re-size the array on every input. also I would need this done using basic java beginner code like basic for loops. If anyone could help me, or at least point me in the right direction i would greatly appreciate it.

[HPWebcamAble]

To re size an array, you:

1. Make a new array which is the size you need (probably one larger than the original)
2. Transfer each element from the original array to the new array

Note that usually, a 'list' is used in Java ('list' is an interface, 'Arraylist' is one of the most common implementations) instead of an array.

An arraylist automatically adjusts it size, and since its an object, has various mehtods that make it easier to work with than an array

[dannytech357]

5 hours ago, Darr1en13 said:

Hello, I could really use someones help on this... I have to create a program where a user can infinity enter values (so not a static array) and then when send user is done entering arrays  it adds, averages, etc... the problem i cant figure out to to re-size the array on every input. also I would need this done using basic java beginner code like basic for loops. If anyone could help me, or at least point me in the right direction i would greatly appreciate it.

Some code for what @HPWebcamAble is talking about:

ArrayList<Datatype> arraylistofdata = new ArrayList<Datatype>();
arraylistofdata.add(Instance of Datatype);
arraylistofdata.get(index of item);

Those are the most common things you will likely use, the first declares an arraylist of a data type, the second adds an element to the list, and the third one gets the element at that index in the arraylist. Happy coding 

[vorticalbox]

personally i would would pick a big number, i highly doubt a user will type in that many. less than a 100 i would say.

[Severin]

13 hours ago, dannytech357 said:

Some code for what @HPWebcamAble is talking about:

ArrayList<Datatype> arraylistofdata = new ArrayList<Datatype>();
arraylistofdata.add(Instance of Datatype);
arraylistofdata.get(index of item);

Those are the most common things you will likely use, the first declares an arraylist of a data type, the second adds an element to the list, and the third one gets the element at that index in the arraylist. Happy coding 

I would say ArrayList like Dannytech357.

 

Take a look here: http://tutorials.jenkov.com/java-collections/list.html

It's the basic on how to use it.

[Nineshadow]

Tbh, you can make just a really big array and use that one.

ifstream in(/*...*/);
int v[10000],n=0;
while(in>>v[n++])
{
//etc.
}

Or you could use a dynamic data structure,like a linked list. Working with pointers is not that fast though, so a dynamic vector would probably be faster.

vector<int> v;
int temp;
while(in>>temp)
  v.push_back(temp);