changed the code a little bit

I changed the code a little bit and put in some comments.

sorting/BucketSort.c

@@ -4,6 +4,7 @@
 */
 #include <stdio.h>
 #include <stdlib.h>
+#include <assert.h>
 
 #define NARRAY 8  /* array size */
 #define NBUCKET 5 /* bucket size */
@@ -30,12 +31,15 @@ void BucketSort(int arr[])
     buckets = (struct Node **)malloc(sizeof(struct Node*) * NBUCKET);
 
     /* initialize pointers to the buckets */
-	for(i = 0; i < NBUCKET;++i) {  
+    for(i = 0; i < NBUCKET; ++i)
+    {
         buckets[i] = NULL;
     }
 
     /* put items into the buckets */
-	for(i = 0; i < NARRAY; ++i) {	
+    /* creates a link list in each bucket slot */
+    for(i = 0; i < NARRAY; ++i)
+    {
         struct Node *current;
         int pos = getBucketIndex(arr[i]);
         current = (struct Node *) malloc(sizeof(struct Node));
@@ -45,41 +49,51 @@ void BucketSort(int arr[])
     }
 
     /* check what's in each bucket */
-	for(i = 0; i < NBUCKET; i++) {
+    for(i = 0; i < NBUCKET; i++)
+    {
         printf("Bucket[\"%d\"] : ", i);
         printBuckets(buckets[i]);
         printf("\n");
     }
 
     /* sorting bucket using Insertion Sort */
-	for(i = 0; i < NBUCKET; ++i) {  
+    for(i = 0; i < NBUCKET; ++i)
+    {
         buckets[i] = InsertionSort(buckets[i]);
     }
 
     /* check what's in each bucket */
     printf("--------------\n");
     printf("Buckets after sorted\n");
-	for(i = 0; i < NBUCKET; i++) {
+    for(i = 0; i < NBUCKET; i++)
+    {
         printf("Bucket[\"%d\"] : ", i);
         printBuckets(buckets[i]);
         printf("\n");
     }
 
     /* put items back to original array */
-	for(j =0, i = 0; i < NBUCKET; ++i) {	
+    for(j =0, i = 0; i < NBUCKET; ++i)
+    {
         struct Node *node;
         node = buckets[i];
-		while(node) {
+        while(node)
+        {
+
+            // precondition for avoiding out of bounds by the array
+            assert(j < NARRAY);
             arr[j++] = node->data;
             node = node->next;
         }
     }
 
     /* free memory */
-	for(i = 0; i < NBUCKET;++i) {	
+    for(i = 0; i < NBUCKET; ++i)
+    {
         struct Node *node;
         node = buckets[i];
-		while(node) {
+        while(node)
+        {
             struct Node *tmp;
             tmp = node;
             node = node->next;
@@ -95,41 +109,50 @@ struct Node *InsertionSort(struct Node *list)
 {
     struct Node *k,*nodeList;
     /* need at least two items to sort */
-	if(list == 0 || list->next == 0) { 
+    if(list == NULL || list->next == NULL)
+    {
         return list;
     }
 
     nodeList = list;
     k = list->next;
-	nodeList->next = 0; /* 1st node is new list */
-	while(k != 0) {	
+    nodeList->next = NULL; /* 1st node is new list */
+    while(k != NULL)
+    {
         struct Node *ptr;
         /* check if insert before first */
-		if(nodeList->data > k->data)  { 
+        if(nodeList->data > k->data)
+        {
             struct Node *tmp;
             tmp = k;
-			k = k->next; 
+            k = k->next; // important for the while
             tmp->next = nodeList;
             nodeList = tmp;
             continue;
         }
 
-		for(ptr = nodeList; ptr->next != 0; ptr = ptr->next) {
+        // from begin up to end
+        // finds [i] > [i+1]
+        for(ptr = nodeList; ptr->next != NULL; ptr = ptr->next)
+        {
             if(ptr->next->data > k->data) break;
         }
 
-		if(ptr->next!=0){  
+        // if found (above)
+        if(ptr->next != NULL)
+        {
             struct Node *tmp;
             tmp = k;
-			k = k->next; 
+            k = k->next; // important for the while
             tmp->next = ptr->next;
             ptr->next = tmp;
             continue;
         }
-		else{
+        else
+        {
             ptr->next = k;
-			k = k->next;  
-			ptr->next->next = 0; 
+            k = k->next; // important for the while
+            ptr->next->next = NULL;
             continue;
         }
     }
@@ -144,7 +167,8 @@ int getBucketIndex(int value)
 void print(int ar[])
 {
     int i;
-	for(i = 0; i < NARRAY; ++i) { 
+    for(i = 0; i < NARRAY; ++i)
+    {
         printf("%d ", ar[i]);
     }
     printf("\n");
@@ -153,7 +177,8 @@ void print(int ar[])
 void printBuckets(struct Node *list)
 {
     struct Node *cur = list;
-	while(cur) {
+    while(cur)
+    {
         printf("%d ", cur->data);
         cur = cur->next;
     }