postman.c

    /* 
     * C Program to Implement Postman Sort Algorithm
     */
    #include <stdio.h>
     
    void arrange(int,int);
    int array[100], array1[100];
    int i, j, temp, max, count, maxdigits = 0, c = 0;
     
    void main()
    {
        int t1, t2, k, t, n = 1;
     
        printf("Enter size of array :");
        scanf("%d", &count);
        printf("Enter elements into array :");
        for (i = 0; i < count; i++)
        {
            scanf("%d", &array[i]);
            array1[i] = array[i];            
        }
        for (i = 0; i < count; i++)
        {
            t = array[i];        /*first element in t */
            while(t > 0)
            {
                c++;
                t = t / 10;        /* Find MSB */
            }
            if (maxdigits < c) 
                maxdigits = c;   /* number of digits of a each number */
            c = 0;
        }
        while(--maxdigits) 
            n = n * 10;      
     
        for (i = 0; i < count; i++)
        {
            max = array[i] / n;        /* MSB - Dividnng by perticular base */
            t = i;
            for (j = i + 1; j < count;j++)    
            {
                if (max > (array[j] / n))
                {
                    max = array[j] / n;   /* greatest MSB */
                    t = j;
                }
            }
            temp = array1[t];
            array1[t] = array1[i];
            array1[i] = temp;
            temp = array[t];
            array[t] = array[i];
            array[i] = temp;
        }
        while (n >= 1)
        {
            for (i = 0; i < count;)
            {
                t1 = array[i] / n;
                for (j = i + 1; t1 == (array[j] / n); j++);
                    arrange(i, j);
                i = j;
            }
            n = n / 10;
        }
        printf("\nSorted Array (Postman sort) :");    
        for (i = 0; i < count; i++)
            printf("%d ", array1[i]);
        printf("\n");
    }
     
    /* Function to arrange the of sequence having same base */
    void arrange(int k,int n)
    {
        for (i = k; i < n - 1; i++)
        {
            for (j = i + 1; j < n; j++)
            {
                if (array1[i] > array1[j])
                {
                    temp = array1[i];
                    array1[i] = array1[j];
                    array1[j] = temp;
                    temp = (array[i] % 10);
                    array[i] = (array[j] % 10);
                    array[j] = temp;
                }
            }
        }
    }