Extra Credit: write mystrlen1 as a single function without the second parameter int mystrlen2(char* str)

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1 CPSC 122 Study Guide 3: Final Examination The final examination will consist of three parts: Part 1 covers mostly C++. For this, see study guides 1 and 2, exams 1 and 2, and part of exam 3, and quizzes 1 and 2. Approximately eight questions. Part 2 covers lists, stacks, queues and recursion. For this, see part of exam 3, quizzes 3 through 5, and the study guide below. Approximately twelve questions. Part 3 consists of two take-home questions. You may not collaborate with anyone on these. Doing so is a violation of academic honesty. Submit typed answers on a sheet as you arrive for the exam. You don t have to submit them electronically. The take-home questions will each be worth two exam questions. Take-Home Question 1. Given ex50.h and ex50.cpp, write dequeue as specified on ex50.h. Pay particular attention to where the back pointer is placed in the constructor. Take-home Question 2. We have looked at two ways store character strings, first using class string, then using c-style null-terminated strings. Recall there is a function strlen(char* str). If str is a null-terminated string, it will return the number of characters in str, excluding the terminating null character. Write the following function RECURSIVELY without using strlen. This definition of string length should help: Suppose S is a null-terminated string. If S is empty (consists only of \0 ) it s length is 0 Otherwise its length is 1 + length of a string 1 character shorter than S Pre: str points to a null-terminated character array, pos is an index into the array Post: returns the number of characters pointed to by str excluding the null character int mystrlen1(char* str, int pos) Extra Credit: write mystrlen1 as a single function without the second parameter int mystrlen2(char* str) Study Guide for Part 2 1. Be able to write recursive versions of functions that are easily defined recursively. Factorial is an example. 3. Be able draw the tree created by the invocation of a recursive function, say ex41.cpp 4. Which ADT exhibits LIFO behavior? 5. What ADT exhibits FIFO behavior?

2 6. Write the constructor for has-a List Stack whose header file shown below. 7. Using a stack, cause the contents of stk to be displayed in numerical order. You may not change the lines give below. int main() Stack* stk = new Stack(); for (int i = 0; i < 5; i++) stk->push(i); } 8. Write the following function //pre: n is a positive integer //post: returns a pointer to a stack holding the integers [0..n-1] but in reverse order Stack* loadstk(int n) 9. Write a simplified version of the function we developed that checks for balanced parens in an algebraic expression. This one simply returns true if the parens are balanced, false otherwise. It must use a stack. An expression with no parentheses is considered balanced. bool checkparens(char* expression) 10. Write the following function for List below Pre: an instance of List exists Post: item is inserted at the head of list. Use bool insert(int pos, itemtype newitem) bool inserth(itemtype item) 11. Redo problem 10 without using the existing function. 12. Write the constructor for List. 13. Write the destructor for List. 14. Write the constructor for the array-based circular queue. 15. A palindrome is a string that is identical whether read forwards or backwards. ABCBA is a palindrome, ABC is not. Write a short function that, using circular queue and pointer-based stack, returns true if the input is a palindrome, false otherwise. Pre: str is c style spring Post: returns true is str contains a palindrome, false otherwise bool ispal(char* str) 16. What is the Big O complexity of inserth from problem 10?

3 17. What is the Big O complexity of insert in the List header file below? 18. Look at selection sort (ex16.cpp). What is the Big O complexity of the algorithm? typedef int itemtype; struct node itemtype item; node* next; class List List(); List(const List* list); ~List(); bool isempty() const; int getlength() const; bool insert(int pos, itemtype newitem); //inserts anywhere bool remove(int pos); bool get(int pos, itemtype& item); node* ptrto(int pos); //used for inserting items past position 1 bool insert(itemtype newitem); //inserts at the head of the list itemtype* items; int size; //number of items in the list node* head; //array-based stack Stack(int sizein); itemtype peek(); //stack is undisturbed bool isfull(); int size; //size of the stack int numitems; //number of items currently in the stack int top; //position of the top item of the stack itemtype* stuff; //a pointer to the array that holds the contents

4 //has-a list stack using List above Stack(); itemtype peek(); //stack is not disturbed List* list; typedef int itemtype; struct node itemtype item; node* next; //pointer-based stack (recall asgn7) Stack(); itemtype peek(); node* top; //pointer to the top of the stack int size; //number of items on the stack

5 //has-a list queue using List above class Queue Queue(); Queue(Queue* Q); ~Queue(); bool isempty() const; bool enqueue(itemtype item); bool dequeue(); bool getfront(itemtype& item); //queue is not disturbed List* list; //array-based circular queue class Queue Queue(int sizein); ~Queue(); void enqueue(itemtype item); itemtype dequeue(); itemtype getfront(); //queue is undistrubed bool isfull(); int size; //size of the queue int numitems; //number of items currently in the queue int back; //index of end of queue int front; //index of front of queue itemtype* stuff; //a pointer to the array that holds the contents

CS24 Week 4 Lecture 2

CS24 Week 4 Lecture 2 Kyle Dewey Overview Linked Lists Stacks Queues Linked Lists Linked Lists Idea: have each chunk (called a node) keep track of both a list element and another chunk Need to keep track