sample output of tic-tac-toe game singly linked lists in the previous sectionswe presented the array data structure and discussed some of its applications arrays are nice and simple for storing things in certain orderbut they have the drawback of not being very adaptablesince we have to fix the size of the array in advance there are other ways to store sequence of elementshoweverthat do not have this drawback in this sectionwe explore an important alternate implementationwhich is known as the singly linked list linked listin its simplest formis collection of nodes that together form linear ordering the ordering is determined as in the children' game "follow the leader,in that each node is an object that stores reference to an element and referencecalled nextto another node (see figure figure example of singly linked list whose elements are strings indicating airport codes the next pointers of each node are shown as arrows the null object is denoted as it might seem strange to have node reference another nodebut such scheme easily works the next reference inside node can be viewed as link or pointer to another node likewisemoving from one node to another by following next reference is known as link hopping or pointer hopping the first and last node of linked list usually are called the head and tail of the listrespectively thuswe can link hop through the list starting at the head and ending at the tail we can identify the tail as the node having null next referencewhich indicates the end of the list linked list defined in this way is known as singly linked list