c - 从链表中删除节点

Question

我写了一个电话簿，它可以在实体之间搜索，现在我写了一个删除功能但我不知道如何以良好的方式使用它，如果我调用搜索然后删除它如何？我应该在搜索功能上给出一个标志吗？我想当用户输入任何号码，电子邮件，...如果存在删除它我不知道我的删除功能是否正确假设第一次链表不为空

#include <stdio.h>
#include <string.h>
#include <ctype.h>
#include <stdlib.h>
struct node {
char Number[10];
char FirstName[10];
char LastName[10];
char FatherName[10]; 
char Email[20];
char SiteName[30];
struct node *next;
struct node *pre;
};
void print(struct node* list)
{
    printf("FIRSTNAME: "); 
       printf(list->FirstName);
    printf("\n");
    printf("LASTNAME: ");      
    printf(list->LastName);
    printf("\n");
    printf("FATHERNAME: ");    
    printf(list->FatherName);
    printf("\n");
    printf("EMAIL: ");      
    printf(list->Email);
    printf("\n");
    printf("SITENAME: ");   
    printf(list->SiteName);
    printf("\n");
    printf("NUMBER: ");   
    printf(list->Number);

}
void search(struct node* list,char* sr,int option)
{
   struct node *current =list;
    current=current->next;
    switch(option)
    {
    case 1:         
        while(current!=0)
        {       int flag=strcmp(current->Number,sr);
        if(flag==0)
        {           printf("you searched This person!\n");
                    print(current);

                    current=current->next;
        }
    else{   
            current=current->next;
                }
        }           
        break;
case 2:
while(current!=0)
        {
        int flag=strcmp(current->FirstName,sr);
        if(flag==0)
        {           printf("you searched This person!\n");
                    print(current);

                    current=current->next;
        }
    else{   
            current=current->next;
                }
        }                       break;
    case 3:
while(current!=0)
        {
        int flag=strcmp(current->LastName,sr);
        if(flag==0)
        {           printf("you searched This person!\n");
                    print(current);

                    current=current->next;
        }
    else{   
            current=current->next;
                }
        }           
                break;
    case 4:
while(current!=0)
        {
        int flag=strcmp(current->FatherName,sr);
if(flag==0)
        {           printf("you searched This person!\n");
                    print(current);

                    current=current->next;
        }
    else{   
            current=current->next;
                }
        }                   
                break;
    case 5:
while(current!=0)
        {
        int flag=strcmp(current->Email,sr);
    if(flag==0)
        {           printf("you searched This person!\n");
                    print(current);

                    current=current->next;
        }
    else{   
            current=current->next;
                }
        }           
                break;
    case 6: 
while(current!=0)
        {
        int flag=strcmp(current->SiteName,sr);
    if(flag==0)
        {           printf("you searched This person!\n");
                    print(current);

                    current=current->next;
        }
    else{   
            current=current->next;
                }
        }           
                break;
    }


}
void deleteNode(struct node* node)
{
    if(node->next==0 && node->pre==0)//we have just 1 node
    {
    free(node);
    }
    if(node->next!=0 && node->pre!=0)//node is among nodes
      {
    struct node * temp1 = node->next;
    struct node * temp2 = node->prev;
    temp2->next=node->next;
    temp1->pre=temp2;
        free(node);
    }
    if(node->next!=0 && node->pre==0)//begining of the list
    {
    struct node * temp1 = node->next;
    temp1->pre=0;
     free(node);
    } 
    if(node->next=0 && node->pre!=0)//end of the list
    {
    struct node* temp2=node->pre;
        temp2->next=0;
        free(node);
    } 
}
void addNode(struct node *head)
{
        struct node *current = head;
struct  node *newNode = malloc(sizeof(struct node));
puts("*******Now you can insert a new person\n****"); 
                printf("FIRSTNAME: ");     
                gets(newNode->FirstName);
                printf("LASTNAME: ");      
                gets(newNode->LastName);
               printf("FATHERNAME: ");    
                gets(newNode->FatherName);
               printf("EMAIL: ");      
                gets(newNode->Email);
               printf("SITENAME: ");   
              gets(newNode->SiteName);
             printf("NUMBER: ");   
              gets(newNode->Number);
              //create new node
           newNode->next = 0;  // Change 1
 if(current->next==0)
{
current->next=newNode;
newNode->pre=current;
    }        
else    {
        while (current->next != 0)
        {
        current = current->next;

        }
    current->next = newNode;    
    newNode->pre=current;
    }
     //      printf("added later\n");
 }
//*************************************************************************

int main()
{
    printf("please choose your option:\n");
printf("1.search\n2.add\n3.delete\n4.Sort\n5.Edit\n6.show the list\n7.Exit\n");

    struct node *root;   
    struct node *conductor;
    root = malloc( sizeof(struct node) );
        root->next = 0;   
      //  addNode(root);
//  char c=getchar();

        //*********************************
     strcpy(root->FirstName, "root");
      strcpy(root->LastName, "last");   
    //    print(root);    
addNode(root);
addNode(root);
printf("SEARCH\n");
    printf("in which group you want to search?\n");
printf("1.Number\n2.FirstName\n3.LastName\n4.FatherName\n5.Email\n6.Site\n");
int num;
scanf("%d", &num);
    switch(num)
    {
      char s[20];
    case 1:             
    printf("please enter your Number to search!");
    scanf("%s",s);
    search(root,s,num);
    break;
    case 2:
    printf("please enter your FirstName to search!\n");
scanf("%s", s);
    search(root,s,num);
    break;
    case 3:
    printf("please enter your LastName to search!\n");
    scanf("%s", s);
    search(root,s,num);
    break;
    case 4: 
      printf("please enter your FatherName to search!\n");

    scanf("%s", s);
    search(root,s,num);
       break;
    case 5: 
       printf("please enter your Email to search!\n");

       scanf("%s", s);
    search(root,s,num);
      break;
    case 6:
    printf("please enter your Site to search!\n");

    scanf("%s", s);
    search(root,s,num);
    break;  
        }

    return 0;
}

Answer 1

    case 3:
    while(current!=0)
    {
      int flag=strcmp(current->LastName,sr);
      if(flag==0)
      {           
         printf("you searched This person!\n");
         print(current);
         deletenode(current)
      }
      else{   
        current=current->next;
      }
     }           
     break;

您可能想更改您的deletenode 函数。我认为你不需要有四个条件。您可以只传递该节点并将其删除。您应该将其设置为 NULL，而不是 0。最好能找到程序中的错误。