moretosearch = (location < length);

Transcription

1 Chapter 3(6th edition): Exercises 1,2,3,9,10,11,12,18-28 (due: 25/10/2017) Solution: 1. (a) Boolean IsThere(ItemType item) Function: Determines if item is in the list. Precondition: List has been initialized. Postcondition: Function value = there exist an item in the list whose key is the same as item's. (b) bool IsThere(ItemType item) const; (c) bool ListType::IsThere(ItemType item) bool moretosearch; int location = 0; found = false; moretosearch = (location < length); while (moretosearch &&!found) switch (item.comparedto(info[location])) case LESS : case GREATER : location++; moretosearch = (location < length); case EQUAL : found = true; (d) bool UnsortedType::IsThere(ItemType item) NodeType* location = listdata; bool found = false; while (!found && location!= NULL) found = location->info.comparedto(item) == EQUAL; location = location->next; 2. (a) Boolean IsThere(ItemType item, UnsortedType list) Function: Determines if item is in the list. Precondition: list has been initialized. Postcondition: Function value = there exist an item in the list whose key is the same as item's.

2 (b) bool IsThere(ItemType item, UnsortedType list) ItemType item2; int counter = 1; bool found = false; list.resetlist(); int length = list.getlength(); while (counter <= length &&!found) list.getnextitem(item2); if (item.comparedto(item2) == EQUAL) found = true; or bool IsThere(ItemType item, UnsortedType list) bool found; list.retrieveitem(item, found); (c) The member function has direct access to the array where the items are stored; the client has to use the class access functions to retrieve each item in turn or call the member function RetrieveItem. The order of IsThere is the same in both cases, but the overhead included in the constant is greater in the client version because of the extra function calls. 3. (a) void UnsortedType::SplitLists(ItemType item, UnsortedType& list1, UnsortedType& list2) int counter = 0; list1.makeempty(); list2.makeempty(); for (counter; counter < list1.getlength(); counter++) if (info[counter].comparedto(item) == GREATER) list2.insertitem(info[counter]); else list1.insertitem(info[counter]); (b) void UnsortedType::SplitLists(ItemType item, UnsortedType& list1, UnsortedType& list2) NodeType* listptr = listdata; while (listptr!= NULL) if (listptr->info <= item) list1.insertitem(listptr->info);

3 else list2.insertitem(listptr->info); listptr = listptr->next; 9. (a) 30 (b) 90 (c) (a) true (b) false (c) false (d)true 11. (a) ok (b) You cannot compare a pointer with what a pointer points to. (c) You cannot compare a pointer with what a pointer points to. (d) You cannot compare a pointer with what a pointer points to. (e) ok (f) ok 12. (a) listdata = ptr1->next; (b) ptr2 = ptr2->next; (c) listdata = NULL (d) ptr1->next->info = (a) p = new int; yes (f) r = NULL; yes (k) delete r; yes (b) q* = new int; no (g) c = *p; yes (l) a = new p; no (c) a = new int; no (h) p = *a; no (m) q* = NULL; no (d) p = r; yes (i) delete b; no (n) *p = a; yes (e) q = b; no (j) q = &c; yes (o) c = NULL; yes 19. Add temp = new int; #include <iostream> using namespace std; int main() int* ptr; int* temp; The first output line is trying to print the pointer rather than what it points to; it should be cout << *ptr << *temp; Without this change you would get output, but it would be meaningless. The line that is storing the number 5 is trying to store it into the pointer rather than what it points to; it should be *ptr = 5;

4 int x; ptr = new int; *ptr = 4; temp = new int; *temp = *ptr; cout << *ptr << *temp; x = 9; *temp = x; cout << *ptr << *temp; ptr = new int; *ptr = 5; cout << *ptr << *temp; // output: return 0; Without spacing information, the output is Exercises 20 through 28 refer to blanks in the following code segment. Class UnsortedType public: / /all the prototypes go here. private: int length; NodeType* listdata; ; void UnsortedType::DeleteItem(ItemType item) // Pre: Item is in list NodeType* tempptr; // pointer delete NodeType* predloc; // trailing pointer NodeType* location; // traveling pointer bool found = false; location = listdata; predloc = ; // 20 length--; // Find node to delete. while ( ) // 21 switch ( ) // 22 case GREATER: ; case LESS : predloc = location; location = ; // 23 case EQUAL : found = ; // 24

5 // delete location tempptr = ; // 25 if ( ) // 26 = location->next; // 27 ele predloc->next = ; // 28 delete tempptr; 20. Read the code segment above and fill in blank # 20. A. NULL B. True C. false D. listdata Answer: A 21. Read the code segment above and fill in blank # 21. A. true B.!found C. false D. moretosearch Answer: B 22. Read the code segment above and fill in blank # 22. A. item.comparedto(listdata->info) B. item.comparedto(location->next) C. item.comparedto(location->info) D. item.compareedto(location) Answer: A 23. Read the code segment above and fill in blank # 23.

6 A. item B. *location.next C. (*location).next D. predloc Answer: C 24. Read the code segment above and fill in blank # 24. A. false B. true C. predloc == NULL D. location!= NULL Answer: B 25. Read the code segment above and fill in blank # 25. A. preloc B. location C. predloc->next D. location->next Answer: B 26. Read the code segment above and fill in blank # 26. A. predloc == NULL B. location == NULL C. predloc == location D. predloc->next == NULL Answer: A 27. Read the code segment above and fill in blank # 27. A. predloc B. location

7 C. location->next D. listdata Answer: D 28. Read the code segment above and fill in blank # 28. A. listdata B. predloc->next C. location->next D. newnode->next Answer: C