List and array question

Question

If you had a realworld app that say accepted new patients into a hospitol, using an array to enter patient objects could possibly fill and exceed array size.  So we can use a List<> But Lists only accept references to ready made objects, usually from an oject[array] so it seems were back to square one?   Are there other solutions?

I am having a lot of trouble articulating this question, please advise if not clear enough... I can try an example with code

 

Thanks,
  Robert

Answer 1

If one has so many records, that is a situation where one is saving/accessing the data in a database. List<> is a perfect vehicle for such operations. Its unclear why one would need to load more than 100 records at a time...but I am sure you will let us know what you need. How many records are we looking at here?

---

William Wegerson (www.OmegaCoder.Com)

Answer 2

Thanks William,

 So you would just make an array of 100 size and if it get near max just increase it in size.

It's all hypothetical William, but a very real challenge because some databases will quick exceed 100 in a short time.  I was wondering about this because as I learned of Lists at first I thought I could replace the common array,
like ~

patients[] patobjdb = new patients[100];       

// ~ lets say in 4 hours we get 90 patients so now patobjdb[0 to 89] are filled with real active cases, say patient records
// ~ a warning program activates maybe requesting permission to make the array larger

because to use List<patients> patdb =new List<patients>();  

// List is unlimited: but that doesn't help anything here, the object array patobjdb[needs increase]
// So the only thing I can think of is:

    1.  making a second temporary array  and copy all of patobjdb in that array
    2.  find a way to use a destructor for the patobjdb array
    3. then re-define patobjarray to a size of 200

Is there any better solutions than this painful solution?
 

Answer 3

 So you would just make an array of 100 size and if it get near max just increase it in size.

No. I would use a List<> with no specified size and add objects as needed.

It's all hypothetical William, but a very real challenge because some databases will quick exceed 100 in a short time.  I was wondering about this because as I learned of Lists at first I thought I could replace the common array,

I disagree. I have had an application running multiple dictionaries which contained internal lists which exceeded thousand of records at a time being read from a database and written out in a conversion operation. Modern computers can handle large array sizes with large objects with no problem.

My point is that one is only looking at a certain number records at a time....not every one of them.

 

    1.  making a second temporary array  and copy all of patobjdb in that array
    2.  find a way to use a destructor for the patobjdb array
    3. then re-define patobjarray to a size of 200

Is there any better solutions than this painful solution?

Just create and use a List<> don't worry about sizes. Its unclear why you need to load every record at once. Its stored in a database correct?

---

William Wegerson (www.OmegaCoder.Com)

Answer 4

I might be testing your patience but I want to take a few baby steps into your explanantion:

   Ok so I make the List<> perhaps as a type dictionary to use like a database and store it to a disk/file;   no problems here, understood.

But then lets say i need to enter 3 new records into the database,   

my_record_input( record R1)        // where R1 represents for example Jim's record  

~save it to List<> then save it to disk-file then next

my_record_input( record R1)        // where R1 now represents for example Bob's record

~save it to List<> then save it to disk-file then next

my_record_input( record R1)        // where R1 now represents for example Sam's record

~save it to List<> then save it to disk-file then next


In the above example R1 was reused for all 3 record entries, is that the way you do it, do you re-use the interface input'ed object?


Thanks,
  Robert

Answer 5

No worries on patience....If R1 is a reference to a different record object no problem. I suggest you work on a test version to start you on the process. By using the List<>.Add( ) one can add all records as needed. HTH

---

William Wegerson (www.OmegaCoder.Com)