Singly linked lists are data structures made up of nodes that contain data and a link to the next node. The nodes are not stored sequentially in memory. New nodes can be added by allocating a new node, filling its data field, and linking it to the next node. Nodes can be removed by linking the previous node's link to the node after the one being removed. Code examples demonstrate how to create a two node list and insert a new node in the middle.

1. Singly Linked Lists
Steve Paks

2. Curriculum Model
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CS
Here I am
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CS
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Java Language Base
CS : Computer
Science
A : Application

3. Singly Linked Lists
• an ordered sequence of nodes with links
– the node do not reside in sequential locations
– the locations of the nodes may change on different runs
bat
cat
cat
sat
vat
NUL
L

4. Singly Linked Lists(Cont’d)
• Insertion
– get a node that is currently unused; let its address be paddr.
– set the data field of this node to mat
– set paddr’s link field to point to the address found in the link field of the node
containing cat.
– set the link field of the node containing cat to point paddr.
ptr
bat
cat
sat
mat
vat
NULL

5. Singly Linked Lists(Cont’d)
• Deletion
– find the node that immediately precedes mat, which is cat
– set the link field of this node to point to mat’s link field
ptr
bat
cat
mat
sat
vat
NULL

6. Singly Linked Lists(Cont’d)
• Declarations
Class ListNode{
char data;
ListNode link = null;
}
• List insertion
(a)
first
(b)
first
first
second
first
20
second
first
20
second
first
20
second
first
20
second
(c)
– create a two-node list
ListNode create2(){
ListNode first, second;
first = new ListNode();
∙∙∙∙(a)
second = new ListNode(); ∙∙∙∙(b)
second.link = null; ∙∙∙∙(c)
second.data = 20; ∙∙∙∙(d)
∙∙∙∙(e)
first.data = 10;
first.link = second; ∙∙∙∙(f)
return first; ∙∙∙∙(g)
}
second
(d)
(e)
(f)
ptr
(g)
10
10
10

7. Singly Linked Lists(Cont’d)
• List insertion(Cont’d)
– create a two-node list
void insert(){
ListNode temp = new ListNode(); ∙∙∙∙(a)
temp.data = 50;
∙∙∙∙(b)
if(this.link != null){
temp.link = this.link.link; ∙∙∙∙(c)
this.link.link = temp; ∙∙∙∙(d)
} else {
temp.link = null; ∙∙∙∙(c’)
this.link = temp; ∙∙∙∙(d’)
}
}

8. Singly Linked Lists(Cont’d)
• List insertion(Cont’d)
– create a two-node list(Cont’d)
(b)
(a)
temp
50
temp
temp
ptr
(c)
10
first
50
temp
ptr
(d)
20
second
10
first
20
second
50
temp
(c’)
ptr
(d’)
50
temp
50
temp