#include <stdio.h>
#include <stdlib.h>
#include <string.h>

/*
* Constants
*/
#define FALSE 0
#define TRUE 255

/*
* Definition of type ListNode
*/
typedef struct Node
{
int data;
struct Node *next;
} ListNode;

/*
* Declarations of functions
*/
int isNumber(char * str);
ListNode * newList(void);
ListNode * insertNode(ListNode * prev, int data);
ListNode * createList(ListNode * head, int numVals, int lowVal, int range);
ListNode * createBuckets(ListNode * bHeads[10], ListNode * bTails[10]);
void printList(ListNode * head, char * prefix, int index);
int getExponent(int highVal);
void deleteList(ListNode * head);
ListNode * removeNode(ListNode * prev);
void setBucketTails(ListNode * bHeads[10], ListNode * bTails[10]);
int length(ListNode * head);
void listToBuckets(ListNode * head, ListNode * bTails[10], int n, int numVals);
void bucketsToList(ListNode * tail, ListNode * bHeads[10]);
int power(int n);
int printUsage(void);
void deleteBuckets(ListNode * bHeads[10]);

/*
* The main function - entry point
*/
int main(int argc, char** argv)
{
int numVals, lowVal, highVal, returnValue = 0;

// Check if the program was called properly
if ((argc == 5) && (isNumber(argv[1])) && (isNumber(argv[2])) && (isNumber(argv[3])) && (isNumber(argv[4])) && ((numVals = atoi(argv[2])) > 0) && ((lowVal = atoi(argv[3])) < (highVal = atoi(argv[4]))))
{

   // set the random generator seed
   srand(atoi(argv[1]));

   // head of the list that has to be sorted, gets a dummy value
   ListNode * sHead = newList();

   // tail of the list that has to be sorted, points to last element in the list
   ListNode * sTail = createList(sHead, numVals, lowVal, highVal - lowVal);

   // heads and tails of 10 buckets
   ListNode * bHeads[10], * bTails[10];

   // Check if list and buckets are created properly - there is no NULL
   if (sHead && sTail && createBuckets(bHeads, bTails))
   {

         // Print the unsorted list
         printList(sHead, "S", 0);

         // loop max number of digits time
         for (int i = 0; i < getExponent(highVal) - 1; i++)
         {

            // set bucket tails to heads
            setBucketTails(bHeads, bTails);

            // move elements from list to buckets by ith digit
            listToBuckets(sHead, bTails, power(i), numVals);

            for (int j = 0; j < 10; j++)
            {
               printList(bHeads[j], "B", j);
            }

            // move elements from buckets back to list
            bucketsToList(sHead, bHeads);

            printList(sHead, "S", i);
         }

         // print the sorted list
         //printList(sHead, "S", getExponent(highVal) - 1);
   }
   else
   {

         // set return value to error when memory not allocated properly
         returnValue = -1;
   }

   // free memory of buckets
   deleteBuckets(bHeads);

   // free memory of list
   deleteList(sHead);
}
else
{

   // set return value to error when program not called properly
   returnValue = printUsage();
}
return (returnValue);
}

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