Linked List

Create a linked list

class DATA2
    {
        String key;
        String name;
        int age;
    }
    class CLType
    {
        DATA2 nodeData = new DATA2();
        CLType nextnode;
    }

add an element at the end of list

CLType CLAddEnd (CLType head, DATA2 nodeData)
        {
            CLType node, htemp;
            if ((node =new CLType())==null)
            {
                System.out.print("memory error");
                return null;
            }else
            {
                node.nodeData=nodeData; //save data
                node.nextnode=null; //list tail
                if(head == null)
                {
                    head=node;
                    return head;
                }
                htemp=head;
                while(htemp!=null)
                {
                    htemp=htemp.nextnode;
                }
                htemp.nextnode=node;
                return head;
            }
        }

Add an element at the first of list

CLType CLAddFirst(CLType head,DATA2 nodeData)
        {
            CLType node;
            if((node = new CLType())==null)
            {
                System.out.print("memory error");
                return null;
            }else
            {
                node.nodeData=nodeData;
                node.nextnode=head;
                head=node;
                return head;
            }
        }
    

Search for node with keyword

CLType CLFindNode (CLType head,String key)
        {
            CLType htemp;
            htemp=head;
            while(htemp!=null)
            {
                if(htemp.nodeData.key.compareTo(key)==0)
                {
                    return htemp;
                }
                htemp=htemp.nextnode;
            }
            return null;
        }

Insert an element

CLType CLInsertNode(CLType head,String findkey,DATA2 nodeData)
        {
            CLType node,nodetemp;
            if ((node = new CLType())==null)
            {
                System.out.print("memory error");
                return null;
            }
            node.nodeData=nodeData;
            nodetemp=CLFindNode(head,findkey);
            if(nodetemp!=null)
            {
                node.nextnode=nodetemp.nextnode;
                nodetemp.nextnode=node;
            }
            else
            {
                System.out.println("position not found");
            }
            return head;
            
        }

Delete an element

int  CLDeleteNode(CLType head,String key)
        {
            CLType node,htemp;
            htemp=head;
            node=head;
            while(htemp!=null)
            {
                if  (htemp.nodeData.key.compareTo(key)==0)
                {
                    node.nextnode=htemp.nextnode;
                    htemp=null; //release memory
                    return 1 ;
                }
                else
                {
                    node = htemp;
                    htemp=htemp.nextnode;
                }
            }
            return 0;
        }   

Calculate the length of linked list

int CLLength(CLType head)
        {
            CLType htemp;
            int len=0;
            htemp=head;
            while(htemp!=null)
            {
                len++;
                htemp=htemp.nextnode;
            }
            return len;
        }