Sorting Problem (Urgent)

[Ramandeep]

Hi, I've just written a sort method for my top ten songs chart program, which just hold a list of the top ten songs.

Each records is made up off the following fields:

Chart Position :int
Song Title :string
Song Artist :string
Record Company :string
Price :double

The method sorts records by Chart Position fine, but when I try to sort by Song Artist and re compile it gives me a error like the following error:

"cannot apply > to string" or somthing.

How can I compaire the strings to see which is greater, I want to sort Song Artist alphabeticly.
Here is how I'm sorting by Chart Position (I'm using bubble sort as you cannot have more than 10 records).

passes = 1;
			swap = true;
			
			while ( ( passes <= arrayToSort.length - 1 ) && ( swap = true ) )
			{
			    i = 0;
			    swap = false;

			    while ( i <= arrayToSort.length - 2 )
			    {
			        if ( arrayToSort[i].chartPosistion > arrayToSort[i + 1].chartPosistion )
			        {
				    tempRecord.chartPosistion = arrayToSort[i].chartPosistion;
				    tempRecord.songTitle = arrayToSort[i].songTitle;
				    tempRecord.songArtist = arrayToSort[i].songArtist;
				    tempRecord.recordCompany = arrayToSort[i].recordCompany;
				    tempRecord.price = arrayToSort[i].price;

				    arrayToSort[i].chartPosistion = arrayToSort[i + 1].chartPosistion;
				    arrayToSort[i].songTitle = arrayToSort[i + 1].songTitle;
				    arrayToSort[i].songArtist = arrayToSort[i + 1].songArtist;
				    arrayToSort[i].recordCompany = arrayToSort[i + 1].recordCompany;
				    arrayToSort[i].price = arrayToSort[i + 1].price;

				    arrayToSort[i + 1].chartPosistion = tempRecord.chartPosistion;
				    arrayToSort[i + 1].songTitle = tempRecord.songTitle;
				    arrayToSort[i + 1].songArtist = tempRecord.songArtist;
				    arrayToSort[i + 1].recordCompany = tempRecord.recordCompany;
				    arrayToSort[i + 1].price = tempRecord.price;
				    
				    swap = true;
			        }
			        
			        i = i + 1;
			    }
			    
			    passes = passes + 1;
			}

To sort by Song Artist

I did the same as above but changing the if from:

if ( arrayToSort[i].chartPosistion > arrayToSort[i + 1].chartPosistion )

to:

if ( arrayToSort[i].songArtist > arrayToSort[i + 1].songArtist )

[Dillinger4]

Use the one of the various sort methods from
java.util.Arrays there are many and the one you
probably need is

public static void sort(Object[] a);

Since Strings are objects in java i would
assume that you can fill up an Object array
with the song artists and apply this method to
the array

[Dillinger4]

Im just curious.... it looks like you are storing
the chart position's and the song Artist's in the same
array. So is arrayto sort a string array? And are chart
position and Song artist string types?

You should also use a Vector "java.util.Vector; which
is similar to a Collection in VB. This way you program
wont be limited buy the amount of artists it can store.




if ( arrayToSort[i].chartPosistion > arrayToSort[i + 1].chartPosistion )


if ( arrayToSort[i].songArtist > arrayToSort[i + 1].songArtist )

[Ramandeep]

Yes they are stored in the same array. The array elements are objects of class SongAccount that is defined as follows:

class SongAccount
{
    int chartPosistion;
    
    String songTitle,
           songArtist,
           recordCompany;
    
    double price;
}

I'm mimicking the record effect that other languages usually provide; you know where you can define your own data type.

About the vector thing, I could use it and I would in other circumstances but the assignment specification only say’s the program has to manage 10 song records.

[Dillinger4]

So i guess since your array is storing objects of your
class you should be able to use the
public static void sort(Object[] a); method. Try it
out and tell us if it works

[Ramandeep]

OK I just handed my coursework in yesterday and I completed the programs and it's working in tip top order.

I also sorted out that sorting problem I had, I did the following

if ( arrayToSort[i].songArtist.compareTo ( arrayToSort[i + 1].songArtist ) > 0 )

I didn't try that last suggestion you made Dilenger4 as I had worked the problem before I saw it, but I would like to thank you and the other guys for all the help, really appreciated.

!!! THANKS GUYS !!!