Bubble Sort in JAVA

What is bubble sort?

It is a sorting technique that is based on the comparison.Here we compare adjacent element, if the first element is larger than the second we swap each other. We do the same procedure again and again until array do not sort completely.

Example:-
5 1 4 2 8

 5 1 4 2 8 

here pass is nothing but iterating the loops equal to number of elements in the array but if it already sorted before then we can break the loop anddo exist

PASS1
case0 1 //check 0 and first element
 1 5 4 2 8 
case1 2 //check 1 and 2 element
 1 4 5 2 8 
case2 3
 1 4 2 5 8 
case3 4
 1 4 2 5 8 
swap istrue

PASS2 //first pass completed now do second pass
case0 1
 1 4 2 5 8 
case1 2
 1 2 4 5 8 
case2 3
 1 2 4 5 8 
case3 4
 1 2 4 5 8 
swap istrue
PASS3 // third pass

case0 1
 1 2 4 5 8 
case1 2
 1 2 4 5 8 
case2 3
 1 2 4 5 8 
case3 4
 1 2 4 5 8 
swap isfalse

since swap is false we break from the loop and do not go for fourth and fifth pass

Program:-

package sorting;

public class BubbleSort {
 
 //function to print array
 public static void print(int[] arr)
 {
  for(int i=0;i<=arr.length-1;i++)
   System.out.print(" "+arr[i]);
  System.out.println(" ");
 }
 
 //function to swap elements
 public static int[] swap(int[] arr,int i, int j)
 {
  int temp;
  temp=arr[i];
  arr[i]=arr[j];
  arr[j]=temp;
  
  return arr;
 }
 
public static void main(String[] args)
{
 int[] arr={5,1,4,2,8};
 print(arr);
 //declared to check the number of passes
 int pass=1;

 while(pass!=arr.length)
 {
  /*declared to check if there is no swap then we are 
  working on already sorted array and can break the loop */
 boolean swap=false;
 
 System.out.println("PASS"+pass);
 
 for(int i=0;i<arr.length-1;i++)
 { 
   if(arr[i]>arr[i+1])
   {
    arr=swap(arr,i,i+1);
    swap=true;
   }
   
   System.out.println("case"+i+" "+(i+1));
   
   print(arr);
  }


System.out.println("swap is"+swap);
if(swap==false)
{
 break;
}
pass++;
 }

}
 
}