pigeonhole.c

    /*
     *  C Program to Implement Pigeonhole Sort
     */
    #include <stdio.h>
     
    #define MAX 7
     
    void pigeonhole_sort(int, int, int *);
    void main()
    {
        int a[MAX], i, min, max;
        printf("enter the values into the matrix :");
        for (i = 0; i < MAX; i++)
        {
            scanf("%d", &a[i]);
        }
        min = a[0];
        max = a[0];
        for (i = 1; i < MAX; i++)
        {
            if (a[i] < min)
            {
                min = a[i];
            }
            if (a[i] > max)
            {
                max = a[i];
            }
        }
        pigeonhole_sort(min, max, a);
        printf("Sorted order is :\n");
        for (i = 0; i < MAX; i++)
        {
            printf("%d", a[i]);
        }
    }
     
    /* sorts the array using pigeonhole algorithm */
    void pigeonhole_sort(int mi, int ma, int * a)
    {
     
        int size, count = 0, i;
        int *current;
        current = a;
        size = ma - mi + 1;
        int holes[size];
        for (i = 0; i < size; i++)
        {
            holes[i] = 0;
        }
        for (i = 0; i < size; i++, current++)
        {
            holes[*current-mi] += 1;
        }
        for (count = 0, current = &a[0]; count < size; count++)
        {
            while (holes[count]--> 0)
            {
                *current++ = count + mi;
            }
        }
    }