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# Bubble Sort

  • Bubble sort is a simple comparison-based algorithm.

  • In which each pair of adjacent elements are compared and swapped, if they are in wrong order.

  • Steps:

    1. n is number of elements, k is pass number
    2. Compare adjacent elements starting from index 0 till index n-k.
    3. If element on left is greater than element on the right, Swap them.
    4. Else, move to the next pair.
    5. At the end of each pass, the greatest element will be at its sorted position.
    6. Repeat the process.

  • We use two nested loops to perform bubble sort, outer loop runs from k=1 to k less than n & Inner loop runs n-k times.

# Source Code - C++

#include <iostream>
using namespace std;

//bubble sort function
void BubbleSort(int A[], int n) {
int flag , k , i, temp;
 //Outer loop
 for( k=1; k<n ; k++)
 {
  flag = 0;
   //inner loop
   for( i=0 ; i<n-k ; i++)
   {
    if(A[i] >A[i+1])
    {
    //swapping
    temp = A[i];
    A[i] = A[i+1];
    A[i+1] = temp;
    //setting flag to 1
    flag = 1;
    }
   }
  // if flag==0 means no swaps i.e. array is sorted
  if(flag == 0 )
  break;
  }
}

void displayArray(int A[],int n)
{
 int i;
 for(i=0;i<n;i++)
  cout<<A[i]<<" ";
 cout<<"\n";
}

int main()
{
 int n,i,e;
 cout<<"enter number of elements\n";
 cin>>n;
 int A[n];
 cout<<"enter elements\n";
 for(i=0;i<n;i++)
 cin>>A[i];

 cout<<"Array before sorting:\n";
 displayArray(A,n);

 //calling bubble sort function
 BubbleSort(A,n);
 cout<<"Array after sorting:\n";
 displayArray(A,n);

 return 0;
}

Learn More

  • Bubble Sort