initial commit

main.c

+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdbool.h>
+
+typedef struct node {
+  int val;
+
+  struct node *next;
+} node;
+
+node* NewNode(int value);
+void AddNodeToStartOfList(node **ptr_to_start, int value);
+void AddNodeToEndOfList(node **ptr_to_start, int value);
+void PrintLinkedList(node *start);
+int ListLength(node *start);
+void AddNode(node **ptr_to_start,int value);
+void SortList(node **start);
+
+
+int main(void) {
+  node *head = NULL; 
+  /*AddNodeToStartOfList(&head,2);
+
+  AddNodeToEndOfList(&head,4);
+  AddNodeToEndOfList(&head,6);
+
+  PrintLinkedList(head);
+
+  printf("List Length: %d\n",ListLength(head));
+
+  AddNode(&head,5);
+
+  PrintLinkedList(head);*/
+
+  AddNodeToStartOfList(&head,5);
+  AddNodeToEndOfList(&head,7);
+  AddNodeToEndOfList(&head,2);
+  AddNodeToEndOfList(&head,1);
+  AddNodeToEndOfList(&head,4);
+  AddNodeToEndOfList(&head,3);
+
+  SortList(&head);
+
+  PrintLinkedList(head);
+
+  return 0;
+}
+
+node* NewNode(int value)
+{
+  node *new_node = NULL;                // Create a pointer to a node structure, set it to NULL for safety
+  new_node =malloc(sizeof(node));       // Set aside space in memory for a node structure. If this fails new_node will be set to NULL
+  if (new_node != NULL)                 // Always ensure the node exists before accessing it.
+  {
+    new_node->val = value;              // Set data values as required
+    new_node->next = NULL;              // Set next (and any other pointers to NULL)
+  } 
+  return new_node;
+}
+
+void AddNodeToStartOfList(node **ptr_to_start, int value)
+{
+  /*
+
+  **ptr_to_start is a variable that stores a pointer to a pointer. 
+  It is the address of the variable which stores the address of the first item in the list.
+  **ptr_to_start is the address of head
+  *ptr_to_start is the contents of the variable head, which is the address of the start of the list.
+  If we change *ptr_to_start (note only one * here) we are changing the contents of head. 
+  We are changing which node is the first node in the list.
+  */
+
+   node *temp = NewNode(value);   // Create a new node
+   temp->next = *ptr_to_start;    // Set the new nodes next pointer to point to the start of the list
+   *ptr_to_start = temp;          // Change head to point to the new node
+}
+
+
+void PrintLinkedList(node *start)
+{
+  // Prints the Linked list from *start
+  // Note if you pass in the address of a node half way through the list it will print the
+  // list from that point
+
+//  node *temp = start;             //
+  printf("\n");
+  while (start!=NULL)
+  {
+    printf("%d\n",start->val);
+    start = start->next;
+  }
+}
+
+void AddNodeToEndOfList(node **ptr_to_start, int value)
+{   
+  node *new_node = NewNode(value);
+  node *temp = *ptr_to_start;
+
+  // if list is empty
+  if (*ptr_to_start==NULL)
+  {
+    *ptr_to_start = new_node;
+    return;
+  }
+
+  // If next is NULL we are on the last entry in the list (or we've broken our list!)
+  while (temp->next != NULL)   
+  {    
+    temp = temp->next;         // Change our temp pointer from the current one to temp->next - "moving" us on to the next node
+  } 
+  temp->next = new_node;
+  return;
+}
+
+int ListLength(node *start) {
+  int count = 0;
+  while (start!=NULL) {
+    count += 1;
+    start = start->next;
+  }
+  return count;
+
+}
+
+void AddNode(node **ptr_to_start,int value) {
+   
+  node *current = *ptr_to_start; 
+  node *new_node = NewNode(value);
+
+  
+  if (*ptr_to_start == NULL)  // special case if the list is empty 
+  { 
+    *ptr_to_start = new_node;
+    return;
+  }
+
+
+  while (current != NULL ) 
+  {
+
+    if (current->next->val > value) 
+    {
+      if (ptr_to_start == current)  //if it is smaller than the first value, add to start
+      { 
+        AddNodeToStartOfList(ptr_to_start,value);
+        return;
+      }
+
+      else if (current->next == NULL) //if it hits the end of the list/ add to end
+      {
+        AddNodeToEndOfList(ptr_to_start,value);
+        return;
+      }
+      
+      else //insert the node in betwen two others
+      {
+        node *temp = current->next;
+        current-> next = new_node;
+        new_node->next=temp;
+        return;
+      }
+    }
+
+    else 
+    {
+      current = current->next;
+      }
+  }
+}
+
+void SortList (node **start)
+{
+  node *current = *start;
+  node *nextnode = current->next;
+  node *prev = *start;
+  int count = 0;
+
+  for (count=0;count<ListLength(*start)-1;++count)
+  {
+
+    while (nextnode != NULL)
+    {
+      if (current->val > nextnode->val)
+      {
+        int temp;
+        temp = current->val;
+        current->val = nextnode->val;
+        nextnode->val = temp;
+      }
+
+      prev = current;
+      current = current->next;
+      nextnode = current->next;
+
+    }
+    printf("Count: %d",count);
+    current = *start;
+    nextnode = current->next;
+    prev = *start;
+  }
+}
+