Further improved shuffle algorithm of task 6.06

ch_6/task_06/main.c

@@ -313,17 +313,10 @@ void songs_shuffle (song_t **head) {
         /* Go to next element */
         curr = curr->next;
     }
-    
-    /* Randomly replace to list elements "number of elements"-times */
-    for (int i=0; i<entries; i++) {
-        /* Get a random number between 0 and (entries-1) */
-        int cnt1 = rand()%entries, cnt2;
-        /* Get a second number which differs from the first one */
-        do {
-            cnt2 = rand()%entries;
-        } while (cnt2 == cnt1);
-        /* Swap the two elements */
-        songs_swap(head, cnt1, cnt2);
+    /* Switch every element with a random one */
+    for (int i=1; i<=entries; i++) {
+        /* Swap the current element with a random one */
+        songs_swap(head, i, rand()%entries);
     }
     
     /* A void function has nothing to return */
@@ -347,6 +340,11 @@ void songs_shuffle (song_t **head) {
  ******************************************************************************/
 void songs_swap (song_t **head, int x, int y) {
     /** Preparation before swapping **/
+    /* Check if x and y are the same */
+    if (x == y) {
+        /* No swap needed */
+        return;
+    }
     /* Get address of the first element and store its neighbors */
     song_t *prevX = NULL, *currX = *head;
     for (int i=0; i < x; i++) {
@@ -408,6 +406,7 @@ int main (void) {
     printf("Please enter the name of the directory to scan: ");
     /* Read in the user input */
     fgets(path,STRING_MAX,stdin);
+    /* Terminate the directory path string */
     path[strlen(path)-1] = '\0';
     
     /* Scan directory and read in the songs */