c++实现单链表创建，删除，遍历，插入，修改操作

#include<iostream>
#include<string>
#include<malloc.h>
using namespace std;

struct Node
{
int data;
struct Node* next;
};

struct Node* build_list(int n)
{
Node *head =(struct Node*)malloc(sizeof(Node));
if (head == NULL)
{
cout<<"malloc failed!"<<endl;
return head;
}
head->data = 1;
head->next = NULL;

Node *curNode = head;
for (int i=1;i<n;i++)
{
Node *newNode = (struct Node*)malloc(sizeof(Node));
if (newNode == NULL)
{
cout<<"malloc failed!"<<endl;
return head;
}
newNode->data = i+1;
newNode->next = NULL;

curNode->next = newNode;
curNode = newNode;
}
return head;
}
struct Node* addtail_node_list(struct Node* head, struct Node* newNode)
{
if (head == NULL || newNode == NULL)
{
return head;
}
struct Node* pcurrNode=head;
while(pcurrNode->next != NULL)
{
pcurrNode = pcurrNode->next;
}
if (pcurrNode != NULL)
{
pcurrNode->next = newNode;
newNode->next = NULL;
}
return head;
}

struct Node* addprev_node_list(struct Node* head, struct Node* newNode,int key)
{
if (head == NULL || newNode == NULL)
{
return head;
}
struct Node* pcurrNode = head;
struct Node* pprevNode = NULL;
while(pcurrNode != NULL)
{
if (pcurrNode->data == key)
{
if (pcurrNode == head)
{
newNode->next = head;
head = newNode;
}
else
{
pprevNode->next = newNode;
newNode->next = pcurrNode;
}
break;
}
pprevNode = pcurrNode;
pcurrNode = pcurrNode->next;
}
return head;
}

struct Node* modkey_node_list(struct Node* head, int key, int modval)
{
if(head==NULL)
{
return head;
}

struct Node* pCurrNode=head;
while(pCurrNode!=NULL)
{
if (pCurrNode->data == key)
{
pCurrNode->data = modval;
break;
}
pCurrNode=pCurrNode->next;

}

return head;
}

struct Node* query_node_list(struct Node* head, int key)
{
if(head==NULL)
{
return head;
}

struct Node* pCurrNode=head;
while(pCurrNode!=NULL)
{
if (pCurrNode->data == key)
{
return pCurrNode;
}
pCurrNode=pCurrNode->next;

}

return NULL;
}
struct Node* delete_node_list(struct Node* head, int key)
{
if(head==NULL)
{
cout<<"list is null"<<endl;
return head;
}

struct Node* pCurrNode = head;
struct Node* pPrevNode = NULL;
bool bfind = false;
while(pCurrNode!=NULL)
{
if (pCurrNode->data == key)
{
if(head==pCurrNode)
{
head=pCurrNode->next;
}
pPrevNode->next = pCurrNode->next;
pCurrNode->next = NULL;
free(pCurrNode);

bfind = true;
break;
}
pPrevNode = pCurrNode;
pCurrNode=pCurrNode->next;

}
if (!bfind)
{
cout<<key<<" not find"<<endl;
}
return head;
}

void print_list(struct Node* head)
{
struct Node* pcurrNode=head;
while(pcurrNode!=NULL)
{
cout<<pcurrNode->data<<" ";

pcurrNode = pcurrNode->next;
}
cout<<endl;
}

int main(void)
{
Node *head=build_list(10);
if (head == NULL)
{
getchar();
return -1;
}
cout<<"pint build list"<<endl;
print_list(head);

Node *newNode = (struct Node*)malloc(sizeof(Node));
int newvalue = 57;
if (newNode == NULL)
{
cout<<"malloc failed!"<<endl;
return -1;
}
newNode->data = newvalue;
newNode->next = NULL;
cout<<"construct a new node:"<<newNode<<endl;
addtail_node_list(head,newNode);

Node *tmp = query_node_list(head,newvalue);
cout<<"query the node:"<<tmp<<" key:"<<newvalue<<endl;

modkey_node_list(head,newvalue,27);
cout<<"mod the key "<<newvalue<<" as key "<<27<<endl;
int key = 7;
cout<<"after delete key equal 7"<<endl;
head=delete_node_list(head,key);

print_list(head);

Node *newNode1 = (struct Node*)malloc(sizeof(Node));
if (newNode1 == NULL)
{
cout<<"malloc failed!"<<endl;
return -1;
}
newNode1->data = 7;
newNode1->next = NULL;
head = addprev_node_list(head,newNode1,8);
cout<<"after add key of 8"<<endl;
print_list(head);

getchar();

return 0;
}