Sorting algorithms in java array

Sorting algorithms in java array
There are many sorting algorithms in data structures world each having their own pros and cons.
let's see how these searching algorithms can be implemented in Java using arrays. 
Below are the implemented searching algorithms  in the below example code.

  •     Implement bubble sort in java.
  •     Implement selection sort in java.
  •     Implement insertion sort in java.
  •     Implement quick sort in java.
  •     Implement merge sort in java.
Sorting class code : 

package com.krish.sorting;

import java.util.Random;

public class SortingTechniques {
 // Applies selection sort technique to the given array
 public static int[] doSelectionSort(int[] arr) {
  for (int i = 0; i < arr.length - 1; i++) {
   int index = i;
   for (int j = i + 1; j < arr.length; j++) {
    if (arr[j] < arr[index]) {
     index = j;
    }
   }
   int smallerNumber = arr[index];
   arr[index] = arr[i];
   arr[i] = smallerNumber;
  }
  return arr;
 }

 // Applies bubble sort technique to the given array
 public static int[] doBubbleSort(int[] arr) {
  int n = arr.length;
  int k;
  for (int m = n; m >= 0; m--) {
   for (int i = 0; i < n - 1; i++) {
    k = i + 1;
    if (arr[i] > arr[k]) {
     swapNumbers(i, k, arr);
    }
   }
  }
  return arr;

 }

 // Applies Insertion sorting Technique
 public static int[] doInsertionSort(int[] arr) {
  int temp;
  for (int i = 1; i < arr.length; i++) {
   for (int j = i; j > 0; j--) {
    if (arr[j] < arr[j - 1]) {
     temp = arr[j];
     arr[j] = arr[j - 1];
     arr[j - 1] = temp;
    }
   }
  }
  return arr;
 }

 // Applies Quick sort to the given array
 public static void doQuickSort(int lowerIndex, int higherIndex,int[] myArray) {
  int i = lowerIndex;
  int j = higherIndex;
  // calculate pivot number, I am taking pivot as middle index number
  int pivot = myArray[lowerIndex + (higherIndex - lowerIndex) / 2];
  // Divide into two arrays
  while (i <= j) {
   /**
    * In each iteration, we will identify a number from left side which
    * is greater then the pivot value, and also we will identify a
    * number from right side which is less then the pivot value. Once
    * the search is done, then we exchange both numbers.
    */
   while (myArray[i] < pivot) {
    i++;
   }
   while (myArray[j] > pivot) {
    j--;
   }
   if (i <= j) {
    exchangeNumbers(i, j,myArray);
    // move index to next position on both sides
    i++;
    j--;
   }
  }
  // call quickSort() method recursively
  if (lowerIndex < j)
   doQuickSort(lowerIndex, j,myArray);
  if (i < higherIndex)
   doQuickSort(i, higherIndex,myArray);
 }

 private static void exchangeNumbers(int i, int j,int[] myArray) {
  int temp = myArray[i];
  myArray[i] = myArray[j];
  myArray[j] = temp;
 }

 private static void swapNumbers(int i, int k, int[] arr) {
  int temp;
  temp = arr[i];
  arr[i] = arr[k];
  arr[k] = temp;
 }

 public static void printArray(int[] printArray) {
  for (int i : printArray) {
   System.out.print(i);
   System.out.print(", ");
  }
 }

 private static int[] getRandomNumbersArray() {
  Random myRandom = new Random();
  int[] randomArray = { myRandom.nextInt(100), myRandom.nextInt(20),
    myRandom.nextInt(600), myRandom.nextInt(60),
    myRandom.nextInt(200) };
  return randomArray;
 }

 public static void main(String[] args) {

  int[] myArray = getRandomNumbersArray();
  System.out.println("\nBefore Selection sort:");
  printArray(myArray);
  System.out.println("\nAfter Selection sort:");
  printArray(doSelectionSort(myArray));
  
  myArray = getRandomNumbersArray();
  System.out.println("\nBefore Bubble sort:");
  printArray(myArray);
  System.out.println("\nAfter Bubble sort:");
  printArray(doSelectionSort(myArray));
  
  myArray = getRandomNumbersArray();
  System.out.println("\nBefore Insertion sort:");
  printArray(myArray);
  System.out.println("\nAfter Insertion sort:");
  printArray(doSelectionSort(myArray));
  myArray = getRandomNumbersArray();
  
  System.out.println("\nBefore Quick sort:");
  printArray(myArray);
  int length = myArray.length;
  doQuickSort(0, length - 1,myArray);
  System.out.println("\nAfter Quick sort:");
  printArray(myArray);
 }
}

 Output : 

Before Selection sort:
10, 0, 480, 41, 175,
After Selection sort:
0, 10, 41, 175, 480,
Before Bubble sort:
77, 3, 91, 4, 8,
After Bubble sort:
3, 4, 8, 77, 91,
Before Insertion sort:
35, 14, 41, 24, 168,
After Insertion sort:
14, 24, 35, 41, 168,
Before Quick sort:
6, 9, 188, 21, 102,
After Quick sort:
6, 9, 21, 102, 188,

References : [1][2]


1 comments to "Sorting algorithms in java array"

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Who ever writes Inappropriate/Vulgar comments to context, generally want to be anonymous …So I hope U r not the one like that?
For lazy logs u can at least use Name/URL option which don’t even require any sign-in, good thing is that it can accept your lovely nick name also and URL is not mandatory too.
Thanks for your patience
~Krishna(I love "Transparency")
వీలయితే నాల్గు పోస్టులు ...కుదురితే ఒక కామెంటూ ...

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