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Insertion sort in C

Insertion sort in C: C program for insertion sort to sort numbers. This code implements insertion sort algorithm to arrange numbers of an array in ascending order. With a little modification, it will arrange numbers in descending order. Best case complexity of insertion sort is O(n), average and the worst case complexity is O(n2).

Insertion sort algorithm implementation in C

/* Insertion sort ascending order */

#include <stdio.h>

int main()
{
  int n, array[1000], c, d, t, flag = 0;

  printf("Enter number of elements\n");
  scanf("%d", &n);

  printf("Enter %d integers\n", n);

  for (c = 0; c < n; c++)
    scanf("%d", &array[c]);

  for (c = 1 ; c <= n - 1; c++) {
    t = array[c];

    for (d = c - 1 ; d >= 0; d--) {
      if (array[d] > t) {
        array[d+1] = array[d];
        flag = 1;
      }
      else
        break;
    }
    if (flag)
      array[d+1] = t;
  }

  printf("Sorted list in ascending order:\n");

  for (c = 0; c <= n - 1; c++) {
    printf("%d\n", array[c]);
  }

  return 0;
}

Output of program:
Insertion sort C program output

Download Insertion sort program.

Best case complexity of insertion sort is O(n), average and the worst case complexity is O(n2).

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