# Implementation of insertion sort and direct selection sort in C basic sorting algorithm

• 2020-05-30 20:35:09
• OfStack

This paper illustrates the implementation of insertion sort and direct selection sort in C basic sorting algorithm. I will share it with you for your reference as follows:

Declares the type of element to be sorted

``````
/*--------------------------
typedef.h
Easy to modify the element type to be sorted
-------------------------------------*/
#ifndef TYPEDEF_H
#define TYPEDEF_H
typedef int T;
#endif

``````

Insertion sort:

``````
/*---------------------------------------------------------------------------------------
Insertion_sort.h
Direct insertion sort
Sort the elements given as an array
The time complexity is ( Reverse order number )N(N-1)/4 = O(N^2), And we're going to get to that in the worst case
At best N Second, worst-case run 2+3+ ... +N
------------------------------------------------------------------------------------------------*/
#ifndef INSERTION_SORT_H
#define INSERTION_SORT_H
#include "typedef.h"
// Direct insertion sort
void Insertion_sort(T *a, int n)
{
for(int i = 1; i != n; ++i)
{
T temp = a[i];
int j = i - 1;
for(; j >= 0 && temp < a[j]; --j )
a[j + 1] = a[j];
a[j + 1] = temp;
}
}
#endif

``````

Direct selection sort:

``````
/*----------------------------------------------
DirectSelection_sort.h
Direct selection sort
Time complexity O(N^2)
--------------------------------------------------------*/
#ifndef DIRECTSELECTION_SORT_H
#define DIRECTSELECTION_SORT_H
#include "typedef.h"
#include "swap.h"
// Sort by direct selection
void DirectSelection_sort(T*a, int n)
{
for(int i = 0; i != n; ++i)
{
int k = i;
for(int j = i; j != n; ++j)
if(a[j] < a[k]) k = j;
swap(a[k],a[i]);
}
}
#endif

``````