Algorithm learning: Selection So

The selection sort algorithm sorts an array by repeatedly finding the minimum element (considering ascending order) from unsorted part and putting it at the beginning. The algorithm maintains two subarrays in a given array.

1. The subarray which is already sorted.
2. Remaining subarray which is unsorted.

In every iteration of selection sort, the minimum element (considering ascending order) from the unsorted subarray is picked and moved to the sorted subarray.

Following example explains the above steps:

arr[] = 64 25 12 22 11

// Find the minimum element in arr[0...4]
// and place it at beginning
11 25 12 22 64

// Find the minimum element in arr[1...4]
// and place it at beginning of arr[1...4]
11 12 25 22 64

// Find the minimum element in arr[2...4]
// and place it at beginning of arr[2...4]
11 12 22 25 64

// Find the minimum element in arr[3...4]
// and place it at beginning of arr[3...4]
11 12 22 25 64

//C program for implentation of seletion sort
#include <stdio.h>

void swap(int *xp,int *yp)
{
    int temp;
    temp = *xp;
    *xp = *yp;
    *yp = temp;
}
void selectionSort(int arr[],int n)
{
    int i,j,min_idx;
    //One by one move boundary of unsorted subarray
    for(i = 0; i < n-1;i++) //variable i is used to control the number of loops
    {//Find the minimum element in unsorted array
        min_idx = i;
        for(j = i+1;j < n;j++)
        {
            if(arr[j] < arr[min_idx])
                min_idx = j;        
        }
        //Swap the found minumum element with the first element 
        swap(&arr[min_idx],&arr[i]);
    }
}
//Function to print an array
void printArray(int arr[],int size)
{
    int i;
    for(i = 0; i < size; i++)
        printf("%d ",arr[i]);
    printf("\n");
}
//Driver program to test above functions
int main()
{
    int Array[] = {64,25,12,22,11};
    int n = sizeof(Array) / sizeof(Array[0]);
    selectionSort(Array,n);
    printf("Sorted Array:\n");
    printArray(Array,n);
    return 0;
}