Diff: doubly_linked_list.cpp

Revision:

1:fbda247b843b

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/doubly_linked_list.cpp	Thu Mar 29 05:05:51 2018 +0000
@@ -0,0 +1,251 @@
+#include <stdlib.h>
+#include <stdio.h>
+#include "doubly_linked_list.h"
+
+DLinkedList* create_dlinkedlist(void) {
+    DLinkedList* newList = (DLinkedList*)malloc(sizeof(DLinkedList));
+    newList->head = NULL;
+    newList->tail = NULL;
+    newList->current = NULL;
+    newList->size = 0;
+    return newList;
+}
+
+LLNode* create_llnode(void* data) {
+    LLNode* newNode = (LLNode*)malloc(sizeof(LLNode));
+    newNode->data = data;
+    newNode->previous = NULL;
+    newNode->next = NULL;
+    return newNode;    
+}
+
+void insertHead(DLinkedList* dLinkedList, void* data){
+  LLNode* newNode = create_llnode(data);
+  if(dLinkedList->head == NULL){
+    dLinkedList->size++;
+    dLinkedList->head = newNode;
+    dLinkedList->tail = newNode;
+  }else{
+    dLinkedList->size++;
+    newNode->next = dLinkedList->head;
+    (dLinkedList->head)->previous = newNode;
+    dLinkedList->head = newNode;
+  }
+}
+
+
+void insertTail(DLinkedList* dLinkedList, void* data){
+  LLNode* newNode = create_llnode(data);
+  if(dLinkedList->tail == NULL){
+    dLinkedList->size++;
+    dLinkedList->head = newNode;
+    dLinkedList->tail = newNode;
+  }else{
+    dLinkedList->size++;
+    newNode->previous = dLinkedList->tail;
+    (dLinkedList->tail)->next = newNode;
+    dLinkedList->tail = newNode;
+  }
+}
+
+int insertAfter(DLinkedList* dLinkedList, void* newData){
+  LLNode* newNode = create_llnode(newData);
+  if(dLinkedList->current == NULL)
+    return 0;
+  else{
+    if(dLinkedList->current == dLinkedList->tail){
+	insertTail(dLinkedList, newData);
+	return 1;
+    }
+    else{
+    	dLinkedList->size++;
+    	newNode->previous = dLinkedList->current;
+    	newNode->next = (dLinkedList->current)->next;
+   	((dLinkedList->current)->next)->previous = newNode;
+    	(dLinkedList->current)->next = newNode;
+	return 1;
+    }
+  }
+
+}
+
+
+int insertBefore(DLinkedList* dLinkedList, void* newData){
+  LLNode* newNode = create_llnode(newData);
+  if(dLinkedList->current == NULL)
+    return 0;
+  else{
+    if(dLinkedList->current == dLinkedList->head){
+	insertHead(dLinkedList, newData);
+	return 1;
+    }
+    else{
+    	dLinkedList->size++;
+    	newNode->next = dLinkedList->current;
+    	newNode->previous = (dLinkedList->current)->previous;
+   	((dLinkedList->current)->previous)->next = newNode;
+    	(dLinkedList->current)->previous = newNode;
+	return 1;
+    }
+  }
+
+}
+
+
+
+void* deleteBackward(DLinkedList* dLinkedList){
+  if(dLinkedList->current == NULL)
+	return NULL;
+  else{
+	if(dLinkedList->current == dLinkedList->head){
+		if((dLinkedList->current)->next == NULL){
+		   free(dLinkedList->head);
+		   dLinkedList->head = NULL;
+		   dLinkedList->tail = NULL;
+		   dLinkedList->current = NULL;
+		   return NULL;
+		}
+		else{
+		   dLinkedList->head = (dLinkedList->current)->next;
+		   free((dLinkedList->head)->previous);
+		   dLinkedList->current = NULL;
+		   return NULL;
+		}
+	}
+	else{
+		if(dLinkedList->current == dLinkedList->tail){
+		   dLinkedList->tail = (dLinkedList->current)->previous;
+		   (dLinkedList->tail)->next = NULL;
+		   free(dLinkedList->current);
+		   dLinkedList->current = dLinkedList->tail;
+		   return (dLinkedList->current)->data;	
+		}
+		else{
+		   ((dLinkedList->current)->next)->previous = (dLinkedList->current)->previous;
+		   ((dLinkedList->current)->previous)->next = (dLinkedList->current)->next;
+		   free(dLinkedList->current);
+		   dLinkedList->current = (dLinkedList->current)->previous;
+		   return (dLinkedList->current)->data;
+		}
+	}
+  }
+
+}
+
+
+
+void* deleteForward(DLinkedList* dLinkedList){
+  if(dLinkedList->current == NULL)
+	return NULL;
+  else{
+	if(dLinkedList->current == dLinkedList->tail){
+		if((dLinkedList->current)->previous == NULL){
+		   free(dLinkedList->tail);
+		   dLinkedList->head = NULL;
+		   dLinkedList->tail = NULL;
+		   dLinkedList->current = NULL;
+		   return NULL;
+		}
+		else{
+		   dLinkedList->tail = (dLinkedList->current)->previous;
+		   free((dLinkedList->tail)->next);
+		   dLinkedList->current = NULL;
+		   return NULL;
+		}
+	}
+	else{
+		if(dLinkedList->current == dLinkedList->head){
+		   dLinkedList->head = (dLinkedList->current)->next;
+		   (dLinkedList->head)->previous = NULL;
+		   free((dLinkedList->head)->previous);
+		   dLinkedList->current = dLinkedList->head;
+		   return (dLinkedList->current)->data;	
+		}
+		else{
+		   ((dLinkedList->current)->next)->previous = (dLinkedList->current)->previous;
+		   ((dLinkedList->current)->previous)->next = (dLinkedList->current)->next;
+		   free(dLinkedList->current);
+		   dLinkedList->current = (dLinkedList->current)->next;
+		   return (dLinkedList->current)->data;
+	
+		}
+	}
+  }
+}
+
+
+void destroyList(DLinkedList* dLinkedList){
+  if(dLinkedList->head != NULL){
+    getHead(dLinkedList);
+    while(deleteForward(dLinkedList)){};
+  }
+  free(dLinkedList);
+}
+
+
+
+void* getHead(DLinkedList* dLinkedList){
+  if (dLinkedList->head == NULL)
+	return NULL;
+  else{
+	dLinkedList->current = dLinkedList->head;
+	return (dLinkedList->head)->data;
+  }
+	
+	
+}
+
+
+
+void* getTail(DLinkedList* dLinkedList){
+  if (dLinkedList->tail == NULL)
+	return NULL;
+  else{
+	dLinkedList->current = dLinkedList->tail;
+	return (dLinkedList->tail)->data;
+  }
+
+}
+
+
+
+void* getCurrent(DLinkedList* dLinkedList){
+  if (dLinkedList->current == NULL)
+	return NULL;
+  else{
+	return (dLinkedList->current)->data;
+  }
+
+}
+
+
+
+void* getNext(DLinkedList* dLinkedList){
+  if (dLinkedList->current == NULL || (dLinkedList->current)->next == NULL)
+	return NULL;
+  else{
+	dLinkedList->current = (dLinkedList->current)->next;
+	return (dLinkedList->current)->data;
+  }
+
+}
+
+
+
+void* getPrevious(DLinkedList* dLinkedList){
+  if (dLinkedList->current == NULL|| (dLinkedList->current)->previous == NULL)
+	return NULL;
+  else{
+	dLinkedList->current = (dLinkedList->current)->previous;
+	return (dLinkedList->current)->data;
+  }
+
+}
+
+
+int getSize(DLinkedList* dLinkedList){
+  return dLinkedList->size;
+
+}
+
+