1.1 Meaning of the fields Please read the textbook's section Revised Sequence ADT-Design Suggestion for information...

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1.1 Meaning of the fields Please read the textbook's section "Revised Sequence ADT-Design Suggestion" for information on the fields. There is a slight difference with the "precursor" pointer. The "precursor" field records the node before the current point in the sequence. If we are at the start of the sequence, then the precursor is null, since there is no node before the first one. In later assignments, we will see how using a dummy" node can simplify the logic, avoiding this special case. If there is no current element, the precursor points to the last node (unlike in the textbook where it points to null). 1.2 The Invariant The invariant is more complex than in the previous implementation. It has the following parts: 1. The list may not include a cycle, where the next link of some node points back to some earlier node. 2. The field manyNodes should accurately represent the number of nodes in the list. 3. The tail pointer points to the last node in the list (if any). 4. The precursor field is either null (in which case, the cursor must be the head) or points to a node in the list (in which case, the cursor must be the next node, if any, in the list). It cannot point to a node no longer in the listthe node must be reachable from the head of the list. We have implemented the first part for you; you should implement the other parts yourself. You should do this early on in developing the implementationit will help you catch bugs as quickly as possible. We provide code to test the invariant checker. 1.1 Meaning of the fields Please read the textbook's section "Revised Sequence ADT-Design Suggestion" for information on the fields. There is a slight difference with the "precursor" pointer. The "precursor" field records the node before the current point in the sequence. If we are at the start of the sequence, then the precursor is null, since there is no node before the first one. In later assignments, we will see how using a dummy" node can simplify the logic, avoiding this special case. If there is no current element, the precursor points to the last node (unlike in the textbook where it points to null). 1.2 The Invariant The invariant is more complex than in the previous implementation. It has the following parts: 1. The list may not include a cycle, where the next link of some node points back to some earlier node. 2. The field manyNodes should accurately represent the number of nodes in the list. 3. The tail pointer points to the last node in the list (if any). 4. The precursor field is either null (in which case, the cursor must be the head) or points to a node in the list (in which case, the cursor must be the next node, if any, in the list). It cannot point to a node no longer in the listthe node must be reachable from the head of the list. We have implemented the first part for you; you should implement the other parts yourself. You should do this early on in developing the implementationit will help you catch bugs as quickly as possible. We provide code to test the invariant checker.