Selection Sort

Selection Sort

Selection sort is a sorting algorithm used to arrange the list of elements in ascending or descending order.
The algorithm divides the list logically into two parts : Sorted and unsorted

Sorting the list in ascending order the algorithm involves by searching for the smallest element in the list and then swapping it with the element at the first position. This swap ensures placing of first element at itssorted position.
Again the sublist from second position is searched for the second smallest element and this second smallest element is swapped with the element at the seond position. this continues till we reache the second last element of the list.

As per this type of sorting algorithm the smallest element is searched and then placed at the first position. After this next smallest element is searched in the list and then exchanged with the element at the second position and so on.

Let us consider an array with following values:

     23,    12,     34,  5,    6,     20

Smallest element is selected

23

12

34

5

6

20

and is exchanged with the element at first position.

5

12

34

23

6

20

 Again second smallest element is selected

5

12

34

23

6

20

and is exchanged with element at second position

5

6

34

23

12

20

Next element at third smallest element is selected

5

6

34

23

12

20

And  isreplaced with third smallest element

5

6

12

23

34

20

Next fourth smallest element is selected

5

6

12

23

34

20

 This fourth smallest element is replaces the element at fourth position

5

6

12

20

34

23

At last the fifth element is selected

5

6

12

20

34

23

And is replaced with element at fifth position

5

6

12

20

23

34

 After five passes this array of six elements is sorted

An array of N elements is sorted with N-1 passes and the last unsorted element is automatically in sorted order.

Algorithm of Selection Sort

1.      Declare a variable MIN to store minimum value.

2.      Declare variable POS to store the p

3.      Declare a temporary variable TEMP.

4.      Declare counter variables S and P .

5.      Set S=0

6.      MIN=AR[S]                                                                     

7.      Set P=S+1

8.      If AR[P]<MIN

  SET MIN=AR[P]

9.      P=P+1

10.  IF (P<N-1) GOTO STEP 8

11.  IF MIN=AR[S] GOTO STEP

12.   TEMP=AR[S]

13.  AR[S]=MIN

14.  AR[POS]=TEMP

15.  S=S+1

16.  IF S<N GOTO STEP 6

17.  STOP

Bubble Sort in C++

// Bubble Sorting
#include<iostream.h>
void main()
{
   int a[20];
   int i,j,n,t;
   cout<<"\n Enter the number of elements(>20) : ";
   cin>>n;
   if(n>20)
      cout<<"\n List size cannot exceed 20 ";
   else
   {
     cout<<"\n Enter the elements : \n ";
     // accepting the list of elements
     for(i=0;i<n;i++)
       cin>>a[i];
     // Sorting
     for(i=0;i<n;i++)
     {  cout<<"\n Pass : "<<i+1;
    for(j=0;j<(n-i);j++)
{
 if(a[j+1]<a[j])
 {
    t=a[j+1];
    a[j+1]=a[j];
    a[j]=t;
 }
}
cout<<"\n";
for(int k=0;k<n;k++)
  cout<<"\t"<<a[k];
     }
     cout<<"\n The sorted list is : ";
     for(i=0;i<n;i++)
       cout<<"\t"<<a[i];
     cout<<"\n Have a nice day ";
 }
 }