Concept explainers
A)
Explanation of Solution
Purpose of the given code:
The given code is trying to print the members of a linked list by traversing through the entire list by using a destructor. A destructor is called when the program ends or the destructor function calls.
Given Code:
//Definition of destructor
NumberList::printList()//Line 1
{//Line 2
//loop
//Error line3
while(head)//Line 3
{//Line 4
/*Print the data value of the node while traversing through the list*/
cout<<head->value; //Line5
/*the pointer is moved one position ahead till end of list */
head= head->next;//Line6
}//Line 7
}//Line 8
Error in the given code:
- In “line 3”, use of the head pointer to walk down the list destroys the list.
- This should be written as an “auxiliary pointer”. So, correct code is given below:
ListNode *nodePtr = head
- This should be written as an “auxiliary pointer”. So, correct code is given below:
while (nodePtr != null)
;&#x...
B)
Explanation of Solution
Purpose of the given code:
The given code is trying to print the members of a linked list by traversing through the entire list by using a destructor. A destructor is called when the program ends or the destructor function calls.
Given Code:
//Definition of destructor
NumberList::PrintList()//Line 1
{//Line 2
//Declaration of structure pointer variables
//Line3
ListNode *p =head; /*the start or head of the list is stored in p */
//loop
//Error Line4
while (p->next) //Line4
{//Line 5
/*Print the data value of node p while traversing through the linklist */
//Line6
cout<<p->value; /*print the individual data values of each node */
//Line7
p=p->next; //the pointer is moved one position ahead till end of list
}//Line8
}//Line9
Error in the given code:
- In “line 4”, eventually the pointer p becomes “NULL”, at which time the attempt to access p->NULL will result in an error.
- This should be written by replacing the text p->next in the while loop with p.
while (p) //Line4
/*Here the loop will traverse till p exists or till p is not NULL */
- The function fails to declare a return type of void...
C)
Explanation of Solution
Purpose of the given code:
The given code is trying to print the members of a linked list by traversing through the entire list by using a destructor. A destructor is called when the program ends or the destructor function calls.
Given Code:
//Definition of destructor
NumberList::PrintList()//Line 1
{//Line 2
//Declaration of structure pointer variables
//Line3
ListNode *p =head; /*the start or head of the list is stored in p */
//loop
// Line4
while (p) //Line4
{//Line 5
/*Print the data value of node p while traversing through the linklist */
//Line6
cout<<p->value; /*print the individual data values of each node */
//Error Line7
//Line7
p++//the pointer is incremented by one position
}//Line8
}//Line9
Error in the given code:
- In “line 7”, the function uses p++ erroneously in place of p=p->next when attempting to move to the next node in the list. This is not possible as increment operator can work only on variables containing data values but here p is a node of a link list which contains an address value pointer pointing to the next list along with a data value.
- This should be written by replacing the text p++ in the while loop body with p=p->next...
D)
Explanation of Solution
Purpose of the given code:
The given code is trying to destroy the members of a linked list by using a destructor. A destructor is called when the program ends or the destructor function calls.
Given Code:
//Definition of destructor
NumberList::~NumberList()//Line 1
{//Line 2
//Declaration of structure pointer variables
ListNode *nodePtr, *nextNode;//Line 3
//Storing "head" pointer into "nodePtr"
nodePtr = head;//Line 4
//loop
while (nodePtr != nullptr)//Line 5
{//Line 6
//Assign address of next into "nextNode"
nextNode = nodePtr->next;//Line 7
//Error
nodePtr->next=nullptr;//Line 8
//Assign nextNode into "nodePtr"
nodePtr = nextNode;//Line 9
}//Line 10
}//Line 11
Error in the given code:
In “line 8”, the address of “next” in “nodePtr” is assigned as “nullptr”.
- This should be written as “delete nodePtr” to delete the value of node from the list, because, “delete” operator is used to free the memory space allocated by the list...
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Chapter 17 Solutions
Starting Out with C++: Early Objects
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