CC-16 : Demonstrate natural sorting using a TreeSet.

Description:

Given a double array arr as input, add its elements to a TreeSet to demonstrate natural sorting using a TreeSet.

Test cases and expected outputs:

Input Parameters	Expected outputs
arr1[]={ 1.0, 4.6, 8.1, 3.7, 4.60, 1, 3.4, 9.5};	Sorted Elements : 1.0,3.4,3.7,4.6,8.1,9.5
arr1[]={ 7.2, 8.0, 5,3};	Sorted Elements : 3.0,5.0,7.2,8.0

Pseudocode:

The java method should accept following input parameters: arr (double array).

Initialize a variable set of type TreeSet to hold the input elements.

Using a for loop iterate through arr, using idx as a loop variable with initial value 0 and increment idx till it reaches arr1.length-1:

Add arr1[idx] to set1.

After the loop completes the double elements of arr have been sorted in ascending order in set.

Initialize a double array retval with size same as set.size().

Use an iterator to access elements from set and add the same to int array retVal. Return retVal.

Code:

public double[] setArrayTreeHash(double[] arr) {
	TreeSet<Double> set=new TreeSet<Double>();
	for (int idx=0; idx < arr.length; idx++) {
		set.add(arr[idx]);
	}
	double retVal[]=new double[set.size()];
	int idx=0;
	Iterator<Double> itr=set.iterator();
	while (itr.hasNext()) {
		retVal[idx]=itr.next().doubleValue();
		idx++;
	}
	return retVal;
}

Click here to download and run code and test cases !

Below fully running code can be copied and run on Eclipse or other Java IDEs. Refer the classname in code below. If the class name below is "A", save the code below to a file named A.java before running it. Be sure to try your own test cases to enhance your understanding ! You can also tweak the code to optimize or add enhancements and custom features.

import java.util.Iterator;
import java.util.TreeSet;

public class SetArrayTreeHash {
	
public double[] setArrayTreeHash(double[] arr) {
	TreeSet<Double> set=new TreeSet<Double>();
	for (int idx=0; idx < arr.length; idx++) {
		set.add(arr[idx]);
	}
	double retVal[]=new double[set.size()];
	int idx=0;
	Iterator<Double> itr=set.iterator();
	while (itr.hasNext()) {
		retVal[idx]=itr.next().doubleValue();
		idx++;
	}
	return retVal;
}




	
public static void main(String[] args) {
		
	SetArrayTreeHash sp=new SetArrayTreeHash();
	double[] retVal;
	try {
	double arr1[]={ 1.0, 4.6, 8.1, 3.7, 4.60, 1, 3.4, 9.5};
	printArraySummary(arr1, "Original Array1");
	retVal=sp.setArrayTreeHash(arr1);
	printArraySummary(retVal, "Common Elements");
			
	double arr2[]={ 7.2, 8.0, 5,3};
	printArraySummary(arr2, "Original Array1");
	retVal=sp.setArrayTreeHash(arr2);
	printArraySummary(retVal, "Common Elements");
			
			
	}catch (Exception exception) {
	System.out.print("Exception,"+ exception);
	exception.printStackTrace();
				
	}
}
			
			
public static void printArraySummary(double[] intArray, String label) throws Exception {
   	// Case 1: The input Array is null !!
	if (intArray == null) { System.out.println("\n\n Input Array was null !! \n"); return; }
	// Case 2: Print input Array by index (first to last)
	System.out.println();
	System.out.println("************************************************************************");
	System.out.print(label+" : ");
	int arrayIndex=0;
	for (arrayIndex=0; arrayIndex< intArray.length; arrayIndex++) {
			System.out.print(intArray[arrayIndex]);
			if (arrayIndex< intArray.length-1) {System.out.print(",");}
	} 
	System.out.println();
	System.out.println("*************************************************************************");
	System.out.println();
	Thread.sleep(2000);
	return;
}			
		

}