我正在尝试获得用户输入，以便在链表中插入元素。如果我尝试在第一或第二位置添加，它会起作用。即使列表中有3个以上的元素，若我在其中放入3个，它也不会工作，也不会返回任何显示语法错误的内容。与变量或循环一起使用错误吗。我非常困惑。
#include<stdlib.h>
#include<stdio.h>
struct Node
{
int data;
Node *next;
};
Node *head;
void insert(int data, int n)
{
Node* temp1 = new Node;
temp1->data = data;
temp1->next = NULL;
if(n == 1)
{
temp1->next = head;
head = temp1;
return;
}
else{
Node *temp2 = head;
for(int i = 0; i = n - 2; i++)
{
temp2 = temp2->next;
}
temp1->next = temp2->next;
temp2->next = temp1;
return;
}
}
void print()
{
Node *temp = head;
while(temp != NULL)
{
printf("%d ", temp->data);
temp = temp->next;
}
}
int main()
{
head = NULL;
insert(3, 1);
insert(33, 1);
insert(384, 2);
insert(384, 1);
insert(432, 3);
insert(34, 4);
print();
}
注释中已经详细说明了明显的错误。额外的东西。
如果这是C++，那么您也应该使用C++语言，尤其是类。
然后根据你的设计。请不要把"；节点"；用"；链表"；。节点是链表的一部分。它包含在链接列表中。它不应该暴露在外界。
如果你想读一点关于链接列表所需功能的内容，那么你可以查看CPP参考。例如这里的
下面列出了一个例子，你可以从中获得更多的想法。
但首先你需要读一本书，这本书是用真正的纸做的：-(
#include <iostream>
#include <iterator>
#include <initializer_list>
#include <algorithm>
// Very simple implementation of a forward list
template <class T>
class SinglyLinkedList {
// The node
struct Node {
T data{}; // Data. Would normally be a templated argument
Node* next{}; // And the pointer to the next node
Node(const T& i, Node* n = nullptr) : data(i), next(n) {}; // Simple constructor to set a value and next pointer
};
Node* head{}; // This is the start of the list
// It would be advisable to have a tail pointer. We use the more inefficient approach here
Node* getLast() const { Node* n{ head }; while (n and n->next) n = n->next; return n; }
public:
// Constructor / Destructor --------------------------------------------------------------------------------------------------------
~SinglyLinkedList() { clear(); }
// Default constuctor
SinglyLinkedList() {} // Default
// From an initialization list
SinglyLinkedList(const std::initializer_list<T>& il) { clear(); for (const T& i : il) push_back(i); } // From initializer list
// Copy constructor
SinglyLinkedList(const SinglyLinkedList& other) { clear(); for (const T& i : other) push_back(i); }
// Move constructor. Will steal the elements from the other
SinglyLinkedList(SinglyLinkedList&& other) noexcept { head = other.head; other.head = nullptr; }
// Assignment operator
SinglyLinkedList& operator = (const SinglyLinkedList& other) { clear(); for (const T& i : other) push_back(i); }
// Move assignment operator
SinglyLinkedList& operator = (SinglyLinkedList&& other) { head = other.head; other.head = nullptr; }
// Housekeeping --------------------------------------------------------------------------------------------------------------
void clear() { Node* tmp{ head }; while (tmp) { Node* toDelete{ tmp }; tmp = tmp->next; delete toDelete; } head = nullptr; }
int empty() const { return head == nullptr; }
int size() const { int k{}; Node* n{ head }; while (n) { ++k; n = n->next; } return k; }
// Modify content --------------------------------------------------------------------------------------------------------------
void push_front(const T& i) { Node* n = new Node(i); n->next = head; head = n; };
void push_back(const T& i) { Node* n = new Node(i); Node* l = getLast(); if (l) l->next = n; else head = n; }
void pop_front() { if (head) { Node* tmp = head->next; delete head; head = tmp; } }
void pop_back() { // This is a little bit more difficult in a singly linked list
if (head) {
Node* n{ head }, * previous{};
while (n and n->next) {
previous = n;
n = n->next;
}
delete n;
if (previous)
previous->next = nullptr;
else
head->next = nullptr;
}
}
// Access elements --------------------------------------------------------------------------------
T& front() const { return head ? head->data : 0; };
T back() const { Node* n = getLast(); return n ? n->data : 0; }
// Add iterator properties to class ---------------------------------------------------------------
struct iterator { // Local class for iterator
Node* iter{}; // Iterator is basically a pointer to the node
// Define alias names necessary for the iterator functionality
using iterator_category = std::forward_iterator_tag;
using difference_type = std::ptrdiff_t;
using value_type = T;
using pointer = T*;
using reference = T&;
// Constructor
iterator() {}
iterator(Node* n) : iter(n) {}
// Dereferencing
reference operator *() const { return iter->data; }
pointer operator ->() const { return &iter->data; }
// Aithmetic operations
iterator& operator ++() { if (iter) iter = iter->next; return *this; }
iterator operator ++(int) { iterator temp{ *this }; ++* this; return temp; }
iterator operator +(const difference_type& n) const { iterator temp{ *this }; difference_type k{ n }; while (k--)++temp; return temp; }
iterator& operator +=(const difference_type& n) { difference_type k{ n }; while (k--)++* this; return *this; };
// Comparison
bool operator != (const iterator& other) const { return iter != other.iter; }
bool operator == (const iterator& other) const { return iter == other.iter; }
bool operator < (const iterator& other) const { return iter < other.iter; }
bool operator > (const iterator& other) const { return iter > other.iter; }
bool operator <= (const iterator& other) const { return iter <= other.iter; }
bool operator >= (const iterator& other) const { return iter >= other.iter; }
// Difference. Also complicated, because no random access
difference_type operator-(const iterator& other) const {
difference_type result{};
Node* n{ iter };
while (n and n != other.iter) {
++result;
n = n->next;
}
return result;
}
};
// Begin and end function to initialize an iterator
iterator begin() const { return iterator(head); }
iterator end() const { return iterator(); }
// Functions typcical for forward lists ----------------------------------------------------------------------
// Easy, becuase we can operate form the current iterator and do not need the "previous" element
iterator insertAfter(iterator& pos, const T& i) {
iterator result{};
if (pos.iter and pos.iter->next) {
Node* n = new Node(i, pos.iter->next);
pos.iter->next = n;
result = n;
}
return result;
}
iterator eraseAfter(iterator& pos) {
iterator result{};
if (pos.iter and pos.iter->next) {
Node* tmp = pos.iter->next->next;
delete pos.iter->next;
pos.iter->next = tmp;
result = pos.iter->next;
}
return result;
}
};
// Test/Driver Code
int main() {
// Example for initilizer list
SinglyLinkedList<int> sllbase{ 5,6,7,8,9,10,11,12,13,14,15 };
// Show move constructor
SinglyLinkedList<int> sll(std::move(sllbase));
// Add some values in the front
sll.push_front(4);
sll.push_front(3);
sll.push_front(2);
sll.push_front(1);
// Delete 1st element (Number 1)
sll.pop_front();
// Delete last element
sll.pop_back();
// Use a std::algorithm on our custom linked list. Works because we have an interator
SinglyLinkedList<int>::iterator iter = std::find(sll.begin(), sll.end(), 8);
// Now add an element after 8
iter = sll.insertAfter(iter, 88);
// End delete the 9
iter = sll.eraseAfter(iter);
// Use range based for loop. Works because, we have iterators
for (int i : sll)
std::cout << i << ' ';
return 0;
}
您的错误在于循环
for(int i = 0; i = n - 2; i++)
存在赋值运算符(=(而不是等于运算符(==(，逻辑也是错误的。
应该是这样的
#include<cstdlib>
#include<cstdio>
struct Node
{
int data;
Node *next;
};
Node *head;
void insert(int data, int n)
{
Node* temp1 = new Node;
temp1->data = data;
temp1->next = NULL;
if(n == 1)
{
temp1->next = head;
head = temp1;
return;
}
else{
Node *temp2 = head;
for(int i = 1; i < n - 1; i++)
{
temp2 = temp2->next;
}
temp1->next = temp2->next;
temp2->next = temp1;
return;
}
}
void print()
{
Node *temp = head;
while(temp != NULL)
{
printf("%d ", temp->data);
temp = temp->next;
}
}
int main()
{
head = nullptr;
insert(3, 1);
insert(33, 1);
insert(384, 2);
insert(384, 1);
insert(432, 3);
insert(34, 4);
print();
}