Sorting Techniques: Selection Sort

I'll start with Selection Sort as my first program here. Sorting is required in various data organising procedures and Selection Sort is one algorithm among several sorting algorithms available. The algorithm is given in the diagram below.



Fact:
In worst-case scenario, Selection Sort makes n(n-1)/2 [Worst-case runtime: Θ(n²)] number of swappings, if n be the total number of elements to be sorted.













Program listing:

/*Program to selection-sort array elements in descending order*/

#include <stdio.h>

#include <conio.h>

void SSort(int num[],int n)

{

int j,k,t;

for(j=0;j<=n-2;j++)

{

for(k=j+1;k<=n-1;k++)

if(num[j]<num[k]) // For ascending order check num[j]>num[k]

{

/*Swapping elements*/

t=num[j];

num[j]=num[k];

num[k]=t;

}

}

}

void main()

{

int num[50],n,i;

clrscr(); // Replace by system("cls") in Visual Studio

printf("How many numbers will you enter? (<=50) ");

scanf("%d",&n);

for(i=0;i<=n-1;i++)

{

/*Entering Data in array*/

printf("Enter #%d ",i+1);

scanf("%d",&num[i]);

}

SSort(num,n);

printf("\nSorted Order:");

for(i=0;i<=n-1;i++)

printf("\n#%d: %d",i+1,num[i]);

getch();

}

Output:

How many numbers will you enter? (<=50) 5

Enter #1 56

Enter #2 78

Enter #3 45

Enter #4 12

Enter #5 92

Sorted Order:

#1: 92

#2: 78

#3: 56

#4: 45

#5: 12