Counting items in specific dimension of multidimensional array (C#)

Question

I am using a multidimensional array to keep track of answers:

public string[,] answersArray = new string[50, 10];

The first dimension of the array keeps track of questions (max. 50 questions), whereas the second dimension keeps track of each question's answers (max. 10). The amount of answers for each question is variable. Upon loading a question, I want to determine the amount of answers for that particular question. Then I can use that amount in a for loop to load and show these answers. Is there an easy way to obtain this, or would I have to write something myself? I know I could just declare another array to keep track of the amount of answers for each question, and just use that to get it done, but I was just wondering if there was an easier solution.

Jon Skeet · Accepted Answer · 2011-05-13 08:53:30Z

8

It sounds like you don't want a rectangular array as you've currently got, but instead an array of arrays, e.g.

string[][] answers = new string[50][];

Then you can populate each array with an array of the right size.

However, another alternative would be to avoid using arrays entirely - use List<T> which will grow as you need it to. In particular, you might want to have a List<Question> where a Question contains the question text itself and a List<Answer> (or possibly just a List<string>) for the answers.

The fact that arrays need to be sized up-front is one reason they should be considered "somewhat harmful".

If you really want to stick with your original approach, then obviously you know you've got 10 elements in each "row" of the array - you'd have to loop to find the first null value (if any) to indicate how many answers have actually been populated.

answered May 13, 2011 at 8:53

Jon Skeet

1.5m893 gold badges9.3k silver badges9.3k bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Jort Over a year ago

In retrospect using Lists would've been better indeed. It's been a while since I last coded in C#, and since the application I'm writing is very small, I started out working with arrays. Thanks for the insight, this is very helpful!

Øyvind Bråthen · Accepted Answer · 2011-05-13 08:57:28Z

3

var dim1 = answersArray.GetLength(0); // 50
var dim2 = answersArray.GetLength(1); // 10

edited May 13, 2011 at 8:57

Øyvind Bråthen

60.9k28 gold badges128 silver badges154 bronze badges

answered May 13, 2011 at 8:53

sehe

400k49 gold badges475 silver badges673 bronze badges

2 Comments

Jort Over a year ago

I found this answer somewhere else as well, but as I said, the amount of answers in the second dimension of the array is variable. Question 1 could have 4 answers, whereas question 2 could have 6 answers, and 3 could have 10.

sehe Over a year ago

Referring to John skeets answer then :)

Collectives™ on Stack Overflow

Counting items in specific dimension of multidimensional array (C#)

2 Answers 2

1 Comment

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

1 Comment

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related