Insertion

Interface

Insertion

Insertion sort permutes an array of values to lie in ascending numerical order.

Insertion sort is one of the most compact sorting algorithms available. However, heap sort beats it in all other criteria. Like the traditional bubble sort, the complexity of insertion sort is:

For this reason, insertion sort should only be considered when code size is an important factor. The algorithm sorts in-place , hence eliminating the need for any extra storage space. The algorithm is also non-recursive, so can never cause a stack overflow in the case of large arrays.

Insertion sort works by maintaining an ordered and an unordered portion of the list. The unordered portion is reduced by adding items one at a time into the ordered portion in the correct place. This is done by shifting values to create gaps .

Example 1

#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <time.h>
 
#include <codecogs/computing/sort/insertion.h>
 
int main()
{
  double vals[25];
  int n=25;
 
  srand((unsigned int) time(NULL));
  for (int i=0; i<n; i++) vals[i]=((double) n*rand())/RAND_MAX;
 
  printf("\nArray to be sorted:\n");
  for (int i=0; i<n; i++) printf("%3.0f ", vals[i]);
 
  Computing::Sort::insertion<double>(vals, n);
 
  printf("\n Sorted array:\n");
  for (int i=0; i<n; i++) printf("%3.0f ", vals[i]);
  printf("\n");
  return 0;
}

Output:

Array to be sorted:
 21  10  20  20  23
  5   8  19   7  14
 12  16   9  13  24
 23  16  18   4  15
  0   6   3  20   4
 
 Sorted array:
  0   3   4   4   5
  6   7   8   9  10
 12  13  14  15  16
 16  18  19  20  20
 20  21  23  23  24

Note

array indexes start at 0

Parameters

array	the array of values to be sorted
n	the number of items in the array

Authors

James Warren (July 2005)

Source Code

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