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Thread: sorting name using Selectionsort

  1. #1
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    Default sorting name using Selectionsort

    hi!
    is there anyone else who can correct my codes?
    i know this is wrong

    here's the problem: Write a class called slectionSort
    this would allow the user to input ten string names (e.g adal, bryan, pius,apple, mango,strawberry, zion, mary, thalea, bon.. . ) and will sort to ascending order using the SelectionSort
    the output will be:
    adal
    apple
    bon
    bryan
    mary
    pius
    strawberry
    thalea
    zion

    and here is my disusting codes
    i can't get it.. maybe its because i use the String.. please help me
    public class selectSort{
      public static void main(String a[]){
        int i;
        String array[] = {. . .};
     
        System.out.println("Data items in original order ");    
        for(i = 0; i < array.length; i++)
          System.out.print( array[i]+"  ");
        System.out.println();
        selection_srt(array, array.length);       
     
        System.out.println("Data items in ascending order");    
        for(i = 0; i <array.length; i++)
          System.out.print(array[i]+"  ");
     
      }
     
      public static void selection_srt(String array[], int n){
        for(int x=0; x<n; x++){
          int min = x;
          for(int y=x; y<n; y++){
            if(array[min]> array[y]){
              min = y;
            }
          }
         String temp = array[x];
          array[x] = array[min];
          array[min] = temp;
        }
      }
    }
    Last edited by helloworld922; May 19th, 2010 at 08:51 PM. Reason: please use [code] tags for code


  2. #2
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    Default Re: sorting name using Selectionsort

    So how do you know it is wrong? If you get any errors, post the full text here.

    Incidentally, you can't compare Strings with relational operators. Use the String.compareTo(..) method.

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    Default Re: sorting name using Selectionsort

    Quote Originally Posted by asdfg View Post
    can't get it.. maybe its because i use the String.. please help me
    try Arrays.sort(yourArray, Collections.reverseOrder());

    import java.util.Arrays;
    import java.util.Collections;
     
    public class javaguitest {
    	public static void main(String[] args) {
    		String[] arr = { "adal", "apple", "bon", "bryan", "mary", "pius",
    				"strawberry", "thalea", "zion" };
     
    		System.out.println(Arrays.toString(arr));
    		Arrays.sort(arr, Collections.reverseOrder());
    		System.out.println("After desc sort: " + Arrays.toString(arr));
    	}
    }

    the output

    [adal, apple, bon, bryan, mary, pius, strawberry, thalea, zion]
    After desc sort: [zion, thalea, strawberry, pius, mary, bryan, bon, apple, adal]
    Last edited by j2me64; May 19th, 2010 at 08:35 AM.

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    Default Re: sorting name using Selectionsort

    Quote Originally Posted by j2me64 View Post
    try Arrays.sort(yourArray, Collections.reverseOrder());
    Really? Is that a Selection Sort?

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    Default Re: sorting name using Selectionsort

    I suspect it's either a quick-sort, or a hybrid sort.

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    Default Re: sorting name using Selectionsort

    Arrays.sort uses a modified quicksort (~ n*(log(n)) )...even it it used selection sort it seems that wouldn't solve your problem of needing to write it yourself. The code you have is on its way, just needs a bit more work in the comparison line (see dlorde's response for a clue)

  7. #7
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    Default Re: sorting name using Selectionsort

    See the modified code.It will work

    import java.util.ArrayList;
    import java.util.Collections;
    import java.util.Vector;
     
    public class selectSort{
     
     
    public static void main(String a[]){
    int i;
    String array[] = {"sdasdasd","asdas","abcd","gyhjhgj"};
     
    System.out.println("Data items in original order "); 
    for(i = 0; i < array.length; i++)
    System.out.print( array[i]+" ");
    System.out.println();
    selection_srt(array, array.length); 
     
    System.out.println("Data items in ascending order"); 
    for(i = 0; i <array.length; i++)
    System.out.print(array[i]+" ");
     
    }
     
     
     
    	public static void selection_srt(String array[], int n) {
    		for (int x = 0; x < n; x++) {
    			int min = x;
    			for (int y = x; y < n; y++) {
    				if (array[min].compareTo(array[y]) > 0) {
    					min = y;
    				}
    			}
    			String temp = array[x];
    			array[x] = array[min];
    			array[min] = temp;
    		}
    }
    }
    We can use compareTo() method of string.

    Result
    Data items in original order
    sdasdasd asdas abcd gyhjhgj
    Data items in ascending order
    abcd asdas gyhjhgj sdasdasd
    Last edited by jnthakar; May 20th, 2010 at 01:21 AM. Reason: please use [code] tags

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    Default Re: sorting name using Selectionsort

    Quote Originally Posted by copeg View Post
    The code you have is on its way, just needs a bit more work in the comparison line (see dlorde's response for a clue)
    No effort needed - someone has fixed the code for him...

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