Selection Sort

Selection sort is a simple method of sorting.Arranging data in ascending order.Just by interchanging of data, which is data X > Y then interchange will takes place.

Algorithm :

Function selection_sort(a, n)

a: list of numbers (array)

n: size of the list.

Step 1: entry

Step 2: for I from 0 to n-2 do the following steps.

             Begin

Step 3: for j from i+1 to n-1 do the following steps.

Begin

Step 4: if a[i] > a[j] then swap i^thelement and j^thelement of array a.

end

end

Step 5: exit

Example  

A[0]             A[1]         A[2]          A[3]           A[4]

25

15

30

10

1

25

15

30

10

1

    Comparing 25 and 15, 25>15 interchange 15and 25

15

25

30

10

1

Compare 15 with 25,30, 10. 15>10 so interchange

10

25

30

15

1

now 10 is comparing with 25,30,15,and1.10>1 interchange

1

15

30

10

25

1 is least data among all,so is placed at A[0] location and it completes First Iteration

1

15

30

10

25

Now comparing 15with 30,10.15>10 interchange

1

10

30

15

25

Now comparing 10 with 30,15,25 no interchange ALL>10

1

10

30

15

25

It shows that completion of Second Iteration

1

10

30

15

25

Now compare 30 with 15. 30 >15 interchange

1

10

15

30

25

 comparing 15 with 30 and 25,15<30,25 no need of interchange.It Completes Third Iteration

1

10

15

30

25

now 30 compared with 25, 30>25 interchange

1

10

15

25

30

 Data is now in sorted order and completes Fourth Iteration

NOTE:In every iteration smallest data is placed in the right location/position