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Recursively reverse an array

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Join Date: Nov 2008

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superbob7

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Recursively reverse an array

Nov 19th, 2008

I was messing around trying to figure this out and came up with this. This works but I'm looking for a more elegant recursive solution. Can anyone think of one? I couldn't find anything with google. Oh and sorry for the stupid variable names.

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 java Syntax (Toggle Plain Text) 
public class arraybackwards {
    public static void main(String[] args){
        int[] bob = {1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18};
        int[] toSend = new int[bob.length];
        int index = 0;
        bob = backwards(bob,toSend,bob.length, index);
        for(int i = 0; i < bob.length; i++){
            System.out.print(bob[i] + " ");
        }
 
    }
 
    public static int[] backwards(int[] arg, int[] toSend, int length, int index){
 
 
        if (length > 0)
	{
                int bob = arg[length-1];
		toSend[index] = bob;
                backwards(arg,toSend,length-1,++index);
 
	}
 
        return toSend;
 
    }
}
public class arraybackwards {
    public static void main(String[] args){
        int[] bob = {1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18};
        int[] toSend = new int[bob.length];
        int index = 0;
        bob = backwards(bob,toSend,bob.length, index);
        for(int i = 0; i < bob.length; i++){
            System.out.print(bob[i] + " ");
        }
        
    }
    
    public static int[] backwards(int[] arg, int[] toSend, int length, int index){
        
        
        if (length > 0)
	{
                int bob = arg[length-1];
		toSend[index] = bob;
                backwards(arg,toSend,length-1,++index);
                
	}
        
        return toSend;

    }
}

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Re: Recursively reverse an array

Nov 19th, 2008

 Help with Code Tags 
 Java Syntax (Toggle Plain Text) 
public class ArrayReverse {
    public static void main(String[] args){
        int[] bob = {1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18};
        int[] newBob = new int[bob.length];
        newBob = reverseArray(bob);
        for(int i = 0; i < bob.length; i++){
            System.out.print(newBob[i] + " ");
        }        
    }
 
    public static int[] reverseArray(int[] arr){
        int[] arrReverse = new int[arr.length];
        int p = 0;     
        for(int i = arr.length -1; i >-1; i--)
        {
        	arrReverse[p] = arr[i];
        	p++;
        }        
        return arrReverse;
    }
}
public class ArrayReverse {
    public static void main(String[] args){
        int[] bob = {1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18};
        int[] newBob = new int[bob.length];
        newBob = reverseArray(bob);
        for(int i = 0; i < bob.length; i++){
            System.out.print(newBob[i] + " ");
        }        
    }
    
    public static int[] reverseArray(int[] arr){
        int[] arrReverse = new int[arr.length];
        int p = 0;     
        for(int i = arr.length -1; i >-1; i--)
        {
        	arrReverse[p] = arr[i];
        	p++;
        }        
        return arrReverse;
    }
}