我有一个程序，我试图制作一个单链表及其复制构造函数。该程序编译成功;然而，在运行时，它打印出它应该输出的一半输出，然后它崩溃（对于糟糕的技术词汇抱歉）而不打印剩余的输出。
我感觉List类中的复制构造函数出了问题，因为程序在到达那一点时崩溃了。
这是我的代码：
# include<iostream>
using namespace std;
class Node
{
public:
int value;
Node* next;
};
class List
{
public:
List();
List(const List &other){
head = new Node;
head = NULL;
Node* temp7;
temp7 = head;
Node* temp6 = other.head;
while (temp6 != NULL)
{
temp7 = new Node;
temp7->value = temp6->value;
temp7 = temp6;
temp6 = temp6->next;
}
}
void push_front(int value){
temporary = new Node;
temporary->value = value;
temporary->next = NULL;
temporary->next = head;
head = temporary;
}
void insert_at(int index, int value){
Node* temp4 = new Node;
temp4->value = value;
temp4->next = NULL;
if (index == 1)
{
temp4->next = head;
head = temp4;
return;
}
Node* temp5 = head;
for (int k = 0; k < index - 2; k++)
temp5 = temp5->next;
temp4->next = temp5->next;
temp5->next = temp4;
}
void remove_at(int index){
Node* temp2 = head;
if (index == 1)
{
head = temp2->next;
delete temp2;
return;
}
for (int j = 0; j < index - 2; j++)
temp2 = temp2->next;
Node* temp3 = temp2->next;
temp2->next = temp3->next;
delete temp3;
}
string printList(void);
private:
Node* head;
Node* temporary;
};
List::List(){
head = NULL;
}
string List::printList(void)
{
Node* temp1 = head;
int counting = 0;
while (temp1 != NULL)
{
cout << "list[" << counting << "] == " << temp1->value << endl;
temp1 = temp1->next;
counting++;
}
}
int main()
{
List list1;
list1.push_front(4);
list1.push_front(3);
list1.push_front(2);
list1.push_front(1);
cout << "list1" << endl;
list1.printList();
cout << endl;
List list2(list1);
cout << "list2" << endl;
list2.printList();
cout << endl;
list1.insert_at(1, 6);
list2.remove_at(2);
cout << "list1" << endl;
list1.printList();
cout << endl;
cout << "list2" << endl;
list2.printList();
cout << endl;
return 0;
}
我无法确定程序中的错误来源。有人可以建议一个解决方案吗？
仅供参考，输出应类似于:(程序仅在崩溃前输出前5行）。
>list1
>
>list[0] == 1
>
>list[1] == 2
>
>list[2] == 3
>
>list[3] == 4
>
>list2
>
>list[0] == 1
>
>list[1] == 2
>
>list[2] == 3
>
>list[3] == 4
>
>list1
>
>list[0] == 1
>
>list[1] == 6
>
>list[2] == 2
>
>list[3] == 3
>
>list[4] == 4
>
>list2
>
>list[0] == 1
>
>list[1] == 2
>
>list[2] == 4
顺便说一句，这是我关于堆栈溢出的第一个问题，所以如果有什么问题或我应该做的事情，请不要犹豫，纠正我。
非常感谢大家的帮助：）
***我解决了这个问题。显然，我没有足够正确地实现复制构造函数。无论如何，谢谢你的所有意见和建议： - ）
//包括标准文件 #include
// Use standard namespace
using namespace std;
// Declare node class
class Node
{
// All values are public; value of node, and next node pointer
public:
int value;
Node* next;
};
// Declare singly linked list class
class List
{
public:
// Declare main constructor
// Declare copy constructor
List();
List(const List ©ing) : head(NULL)
{
// Use a node to move through the source linked list
// Set the size of the new linked list
// For every node in old list, copy it to a new node and link it to the new singly linked list
Node* cur = copying.head;
int size = copying.size();
Node* end = NULL;
for(int q = 0; q < size; q++)
{
Node* n = new Node;
n->value = cur->value;
if (head == NULL)
{
head = n;
end = head;
}
else
{
end->next = n;
end = n;
}
cur = cur->next;
}
end->next = NULL;
}
// Push front a new node
// Add its value and set its next pointer to NULL
void push_front(int value){
temporary = new Node;
temporary->value = value;
temporary->next = NULL;
temporary->next = head;
head = temporary;
}
// Insert node between x and x+1
// Get the new node's value
// Create the new node by moving from the head->next method
// Add the value and set up the node
void insert_at(int index, int value){
Node* temp4 = new Node;
temp4->value = value;
temp4->next = NULL;
if (index == 1)
{
Node* temp9 = head->next;
temp4->next = temp9;
head->next = temp4;
return;
}
Node* temp5 = head;
for (int k = 0; k < index - 2; k++)
temp5 = temp5->next;
temp4->next = temp5->next;
temp5->next = temp4;
}
// Remove node number [index]
// Get the head
// Iterate through the linked list
// When at the node before the one that has to be deleted, set its value to the node after the next one
// Delete the node that should be deleted
void remove_at(int index){
Node* temp2 = head;
if (index == 1)
{
head = temp2->next;
delete temp2;
return;
}
for (int j = 0; j < index - 1; j++)
temp2 = temp2->next;
Node* temp3 = temp2->next;
temp2->next = temp3->next;
delete temp3;
}
// Simple function to pass the head of a singly linked list
// Simple function to get the size of a function
Node * PassHead(void);
int size()const;
private:
Node* head;
Node* temporary;
};
// Returns head
Node * List::PassHead()
{
return head;
}
// Constructor sets head to NULL
List::List(){
head = NULL;
}
// Gets the size of the singly linked list.
// While the node_>next is not NULL, add 1 to counter
// return counter
int List::size()const {
Node* temp1 = head;
int counting = 0;
while (temp1 != NULL)
{
counting++;
temp1 = temp1->next;
}
return counting;
}
// Same function as the size() function, excetp this time, print the node value while iterating through list
// Nothing returned
void printList(List object)
{
Node* temp1 = object.PassHead();
int counting = 0;
while (temp1 != NULL)
{
cout << "list[" << counting << "] == " << temp1->value << endl;
temp1 = temp1->next;
counting++;
}
}
// Declare main function here
int main()
{
// Object of List
List list1;
// Push some values
list1.push_front(4);
list1.push_front(3);
list1.push_front(2);
list1.push_front(1);
// Print the first list
cout << "list1" << endl;
printList(list1);
cout << endl;
// Copy constructor for second list
List list2(list1);
// Print second list
cout << "list2" << endl;
printList(list2);
cout << endl;
// Insert node in first list
list1.insert_at(1, 6);
// Remove node in second list
list2.remove_at(2);
// Print first list
cout << "list1" << endl;
printList(list1);
cout << endl;
// Print second list
cout << "list2" << endl;
printList(list2);
cout << endl;
// Program ran successfully
return 1;
}
答案 0 :(得分：0)
由于此页面上没有足够的分数，我无法回答正常情况。但我找到了一些东西。
List(const List &other){
head = new Node;
head = NULL;
Node* temp7;
temp7 = head;
Node* temp6 = other.head;
while (temp6 != NULL)
{
temp7 = new Node;
temp7->value = temp6->value;
temp7 = temp6;
temp6 = temp6->next;
}
结束括号在哪里？下一个函数将在名为List（const List＆amp; other）{....的函数中创建。 添加一个括号，然后重试。 希望有所帮助;）