Java Insertion Sort doesnt sort

Question

I have written a java sorting algorithm by insertion, the code compiles but doesnt sort:(. If anyone could point out any flaws, Id be very thankful, Java doesnt...

public class Sort {

public static int[] sort(int[] x) {
    int[] y = new int[x.length];
    for(int i = 0; i < x.length; ++i) {
        int j = 0;
        while (y[j] < x[i] && j < i) ++j;
        for (int k = i-1; k >= j; --k) y[k+1] = y[k];
        y[j]=x[i];
    }   
    return y;
}

public static void main(String[] args) {
    int[] size = new int[10];
    for(int k=0; k<size.length; ++k ) {
        size[k]=(int)(Math.random()*20);
        System.out.println(size[k]);
    }
    System.out.println(sort(size));
}}

Thats the output on the console btw: 7 11 15 12 17 8 1 8 17 2 [I@39ed3c8d so the unsorted Array and then just random... — DerStrebsame
– DerStrebsame, Commented Aug 28, 2020 at 14:47
For starters, "while (y[j] < x[i]" references y while y has not been loaded. Your "find insertion point" code should default to 0. The order of boolean expressions protects against things like this, like saying "x != null && x.y > 0" protects x.y from a null x reference. — David G. Pickett
– David G. Pickett, Commented Aug 28, 2020 at 15:34
Everyone is answering about your sysout, but those aren't real solutions. I would recommend just using Arrays.toString() to pretty print your array. docs.oracle.com/javase/7/docs/api/java/util/… — George
– George, Commented Aug 28, 2020 at 17:23

Giorgi Tsiklauri · Accepted Answer · 2020-08-28 17:27:27Z

2

[I@39ed3c8d is returned by invoking toString() on an int array, which you then print with System.out.println.

You presumably want System.out.println(Arrays.toString(sort(size))); instead.

edited Aug 28, 2020 at 17:27

Giorgi Tsiklauri

11.4k9 gold badges59 silver badges84 bronze badges

answered Aug 28, 2020 at 14:51

rzwitserloot

107k6 gold badges74 silver badges104 bronze badges

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

Comments

Idriss Riouak · Accepted Answer · 2020-08-28 14:54:06Z

You are printing the reference of size i.e., [I@39ed3c8d .

This should help you to understand:

public class Sort {

public static int[] sort(int[] x) {
    int[] y = new int[x.length];
    for(int i = 0; i < x.length; ++i) {
        int j = 0;
        while (y[j] < x[i] && j < i) ++j;
        for (int k = i-1; k >= j; --k) y[k+1] = y[k];
        y[j]=x[i];
    }   
    return y;
}

public static void main(String[] args) {
    int[] size = new int[10];
    System.out.println("Befor sorting");
    for(int k=0; k<size.length; ++k ) {
        size[k]=(int)(Math.random()*20);
        System.out.print(size[k]);
        System.out.print(" ");
    }
    size = sort(size);

    System.out.println("\nAfter sorting");
    for(int i = 0; i<size.length; i++){
        System.out.print(size[i]);
        System.out.print(" ");
    }
}}

Lazar Đorđević · Accepted Answer · 2020-08-28 17:17:08Z

0

That random is result of: System.out.println(sort(size));

Do this instead:

size = sort(size);
   for(int k=0; k<size.length; ++k ) {
    
    

 System.out.print(size[k] + " " );
}

edited Aug 28, 2020 at 17:17

Lazar Đorđević

5431 gold badge7 silver badges18 bronze badges

answered Aug 28, 2020 at 14:57

Saurabh Nigam

8237 silver badges12 bronze badges

1 Comment

George Over a year ago

docs.oracle.com/javase/7/docs/api/java/util/…

Collectives™ on Stack Overflow

Java Insertion Sort doesnt sort

3 Answers 3

Comments

Comments

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

Comments

Comments

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related