7. Write a c program for sorting using shell-sort method.

#include <stdio.h>
#include <conio.h>

void shellSort(int a[], int n)
{
    int gap = n / 2;
    while (gap > 0)
    {
        int i = 0;

        for (i = gap; i < n; i++)
        {
            int temp = a[i];
            int j = i;

            while (j >= gap && a[j - gap] > temp)
            {
                a[j] = a[j - gap];
                j = j - gap;
            }
            a[j] = temp;
        }

        gap = gap / 2;
    }
}

void main()
{
    int i;
    int a[9] = {33, 31, 40, 8, 12, 17, 25, 42, 21};

    // int n = sizeof(a) / sizeof(a[0]);

    printf("Before sorting array elements are - \n");
    for (i = 0; i < 9; i++)
        printf("%d ", a[i]);


    shellSort(a, 9);


    printf("\nAfter applying shell sort, the array elements are - \n");
    for (i = 0; i < 9; i++)
        printf("%d ", a[i]);

    getch();
}

Output