Algorithm to array sorting by selection

Here explain array sorting of randomly ordered n integers into ascending order using Selection. Firstly look at unsorted and sorted arrays It is a simple and basic algorithm with simple two steps.
Comparing sorted and Unsorted arrays we can see that it can be done using following steps
1.Find the smallest element in the unsorted array.
2.Place it (smallest element ) in position a[0] .

This process is shown in the figure below.

Algorithm to Sort by selection

 

//This code is for sort first element//
    Min = a[0];
    for(j=1;j<=n;j++){
    if(a[j]<min){
    min = a[j];}}
    a[0]= min;

 

Algorithm to Sort by selection
From the figure, we can see that 3 is to be selected as the smallest element and placed into a[0]. But the problem is 20 is missing that was in previous a[0] position. To avoid this problem we will save the element 20 before 3 placing into a[0]. It can do with a temporary variable. After placing 3 into a[0], 20 from temporary variable need placed into a[6] which is the previous position of 3. Now we successfully sort the first element. Figure illustrate the sorted and unsorted parts. We don’t want to consider sorted part then. In unsorted part, we need to do the same process again and again. how can we write general code?. Before general code just look the figure that an array is sorted by selection in step by step. We can easily grasp the algorithm. Also from the figure, we can see that the array taking 7 steps to sort 8 element array.So in general case, we need (n-1) iteration to sort n element array.

Algorithm to Sort by selection

 

Algorithm Description:    While there are still elements in the unsorted part of the array do

  1. Find the minimum and place it as the first element in unsorted part of the array a[n].
  2. Exchange the min in the unsorted of the array with the first element a[i] in the unsorted array.

Implementation in C:

 

for(i=0;i<=n-2;i++){
      min=a[i];
      for(j=i+1;j<=n;j++){
        if(a[j]<min){ 
          min=a[j];  }
        a[i]=min;                 
    }

 

 

Anwar Yakkiparamban

Anwar Yakkiparamban is the founder of Lauyou Learning. Prior to Lauyou learning, Anwar worked at ARD Engineering & Development, Qatar. He holds bachelor degree in Electronics and Communication Engineering from Govt. Engineering College Idukki.

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