C 链表节点错误无限循环的节点和插入之间的节点

当我创建第三个节点时，它创建了该节点的无限循环。我该怎么办？ 请在某个节点后面插入节点的“b”格中插入代码

第一部分-----------------------------------------------------------------------------------------------------------------------------

#include<stdio.h>
#include<stdlib.h> 
#include<stdbool.h>

char p,j ;
int v;

struct node{
int val;
struct node *next;
};

struct node *head=NULL;
struct node *curr=NULL;
struct node *temp=NULL;
struct node *prev=NULL;
struct node *tail=NULL;
struct node *after=NULL;

struct node *creatFirstNode(int val){

   printf("\ncreating list with headnode as [%d]\n",val);
   struct node *ptr=(struct node *)malloc(sizeof(struct node));
   if(ptr==NULL){
                  printf("\nCreated Failed \n");
                  return NULL;       
   }
   ptr->val=val;
   ptr->next=NULL;

   head=ptr;
   curr=ptr;

  return ptr;
}

main(){
   int  n,i;
   struct node *A=(struct node *)malloc(sizeof(struct node));
   struct node *B=(struct node *)malloc(sizeof(struct node));
   struct node *C=(struct node *)malloc(sizeof(struct node));
   struct node *new=(struct node *)malloc(sizeof(struct node));
   struct node *addEnd=(struct node *)malloc(sizeof(struct node));
   struct node *addAmong=(struct node *)malloc(sizeof(struct node));


   printf("\n-------- Welcome to Linked List Program -----------\n\n");

   do{

   printf("\nAdd to 'h'ead or 't'ail or 'b'ehind value:");   
   scanf("%c",&p); 
   fflush(stdin);

   switch(p)
{
    case 'h':
        printf("Enter value node:");
        scanf("%d",&v);
        fflush(stdin);
        if(head == NULL)
        {
                creatFirstNode(v);
                fflush(stdin);
        }
        else
        {
            curr=head;
            new->val=v;
            new->next=NULL;
            curr=new;
            curr->next=head;
            curr=curr->next;
            ("\ncreating list with headnode as [%d]\n",v);
            head=new;
            fflush(stdin);
        }
        //void printList();

   curr=head;
   printf("\n----Value in Liked list----\n");

   while(curr!=NULL){
              printf("[%d], ",curr->val); 
              curr=curr->next;  //change current node        
                    }
        break;

    case 't':
        printf("Enter value node tail:");
        scanf("%d",&v);



        curr=head;
        while(curr!=NULL){ //Seek for last node
                tail=curr;
                curr=curr->next; // shift to next node

            }

       addEnd->val=v;
       addEnd->next=NULL;
       tail->next=addEnd;        
        tail=new;
       fflush(stdin); 

        //void printList();.
        curr=head;
   printf("\n----Value in Liked list----\n");

   while(curr!=NULL){


              printf("[%d], ",curr->val); 
              curr=curr->next;  //change current node

          }

        break;

    case 'b':
        printf("Enter value node behind:");
        scanf("%d",&v);
        fflush(stdin);

        printf("Adding value [%d] in new node:",&v);
        printf("Add new node behind the value:");


        void printList();
        break;



        default:

        printf("\n     Invalid Input     ");
        getch();


}

}while(p != 'h' || p != 't' || p != 'b' );

getch();  
return 0;
 }

第三部分-----------------------------------------------------------------------------------------------------------------------------

#include<stdio.h>
#include<stdlib.h> 
#include<stdbool.h>

char p,j ;
int v;

struct node{
int val;
struct node *next;
};

struct node *head=NULL;
struct node *curr=NULL;
struct node *temp=NULL;
struct node *prev=NULL;
struct node *tail=NULL;
struct node *after=NULL;

struct node *creatFirstNode(int val){

   printf("\ncreating list with headnode as [%d]\n",val);
   struct node *ptr=(struct node *)malloc(sizeof(struct node));
   if(ptr==NULL){
                  printf("\nCreated Failed \n");
                  return NULL;       
   }
   ptr->val=val;
   ptr->next=NULL;

   head=ptr;
   curr=ptr;

  return ptr;
}

main(){
   int  n,i;
   struct node *A=(struct node *)malloc(sizeof(struct node));
   struct node *B=(struct node *)malloc(sizeof(struct node));
   struct node *C=(struct node *)malloc(sizeof(struct node));
   struct node *new=(struct node *)malloc(sizeof(struct node));
   struct node *addEnd=(struct node *)malloc(sizeof(struct node));
   struct node *addAmong=(struct node *)malloc(sizeof(struct node));


   printf("\n-------- Welcome to Linked List Program -----------\n\n");

   do{

   printf("\nAdd to 'h'ead or 't'ail or 'b'ehind value:");   
   scanf("%c",&p); 
   fflush(stdin);

   switch(p)
{
    case 'h':
        printf("Enter value node:");
        scanf("%d",&v);
        fflush(stdin);
        if(head == NULL)
        {
                creatFirstNode(v);
                fflush(stdin);
        }
        else
        {
            curr=head;
            new->val=v;
            new->next=NULL;
            curr=new;
            curr->next=head;
            curr=curr->next;
            ("\ncreating list with headnode as [%d]\n",v);
            head=new;
            fflush(stdin);
        }
        //void printList();

   curr=head;
   printf("\n----Value in Liked list----\n");

   while(curr!=NULL){
              printf("[%d], ",curr->val); 
              curr=curr->next;  //change current node        
                    }
        break;

    case 't':
        printf("Enter value node tail:");
        scanf("%d",&v);



        curr=head;
        while(curr!=NULL){ //Seek for last node
                tail=curr;
                curr=curr->next; // shift to next node

            }

       addEnd->val=v;
       addEnd->next=NULL;
       tail->next=addEnd;        
        tail=new;
       fflush(stdin); 

        //void printList();.
        curr=head;
   printf("\n----Value in Liked list----\n");

   while(curr!=NULL){


              printf("[%d], ",curr->val); 
              curr=curr->next;  //change current node

          }

        break;

    case 'b':
        printf("Enter value node behind:");
        scanf("%d",&v);
        fflush(stdin);

        printf("Adding value [%d] in new node:",&v);
        printf("Add new node behind the value:");


        void printList();
        break;



        default:

        printf("\n     Invalid Input     ");
        getch();


}

}while(p != 'h' || p != 't' || p != 'b' );

getch();  
return 0;
 }

第四部分-----------------------------------------------------------------------------------------------------------------------------

#include<stdio.h>
#include<stdlib.h> 
#include<stdbool.h>

char p,j ;
int v;

struct node{
int val;
struct node *next;
};

struct node *head=NULL;
struct node *curr=NULL;
struct node *temp=NULL;
struct node *prev=NULL;
struct node *tail=NULL;
struct node *after=NULL;

struct node *creatFirstNode(int val){

   printf("\ncreating list with headnode as [%d]\n",val);
   struct node *ptr=(struct node *)malloc(sizeof(struct node));
   if(ptr==NULL){
                  printf("\nCreated Failed \n");
                  return NULL;       
   }
   ptr->val=val;
   ptr->next=NULL;

   head=ptr;
   curr=ptr;

  return ptr;
}

main(){
   int  n,i;
   struct node *A=(struct node *)malloc(sizeof(struct node));
   struct node *B=(struct node *)malloc(sizeof(struct node));
   struct node *C=(struct node *)malloc(sizeof(struct node));
   struct node *new=(struct node *)malloc(sizeof(struct node));
   struct node *addEnd=(struct node *)malloc(sizeof(struct node));
   struct node *addAmong=(struct node *)malloc(sizeof(struct node));


   printf("\n-------- Welcome to Linked List Program -----------\n\n");

   do{

   printf("\nAdd to 'h'ead or 't'ail or 'b'ehind value:");   
   scanf("%c",&p); 
   fflush(stdin);

   switch(p)
{
    case 'h':
        printf("Enter value node:");
        scanf("%d",&v);
        fflush(stdin);
        if(head == NULL)
        {
                creatFirstNode(v);
                fflush(stdin);
        }
        else
        {
            curr=head;
            new->val=v;
            new->next=NULL;
            curr=new;
            curr->next=head;
            curr=curr->next;
            ("\ncreating list with headnode as [%d]\n",v);
            head=new;
            fflush(stdin);
        }
        //void printList();

   curr=head;
   printf("\n----Value in Liked list----\n");

   while(curr!=NULL){
              printf("[%d], ",curr->val); 
              curr=curr->next;  //change current node        
                    }
        break;

    case 't':
        printf("Enter value node tail:");
        scanf("%d",&v);



        curr=head;
        while(curr!=NULL){ //Seek for last node
                tail=curr;
                curr=curr->next; // shift to next node

            }

       addEnd->val=v;
       addEnd->next=NULL;
       tail->next=addEnd;        
        tail=new;
       fflush(stdin); 

        //void printList();.
        curr=head;
   printf("\n----Value in Liked list----\n");

   while(curr!=NULL){


              printf("[%d], ",curr->val); 
              curr=curr->next;  //change current node

          }

        break;

    case 'b':
        printf("Enter value node behind:");
        scanf("%d",&v);
        fflush(stdin);

        printf("Adding value [%d] in new node:",&v);
        printf("Add new node behind the value:");


        void printList();
        break;



        default:

        printf("\n     Invalid Input     ");
        getch();


}

}while(p != 'h' || p != 't' || p != 'b' );

getch();  
return 0;
 }

第五部分-----------------------------------------------------------------------------------------------------------------------------

#include<stdio.h>
#include<stdlib.h> 
#include<stdbool.h>

char p,j ;
int v;

struct node{
int val;
struct node *next;
};

struct node *head=NULL;
struct node *curr=NULL;
struct node *temp=NULL;
struct node *prev=NULL;
struct node *tail=NULL;
struct node *after=NULL;

struct node *creatFirstNode(int val){

   printf("\ncreating list with headnode as [%d]\n",val);
   struct node *ptr=(struct node *)malloc(sizeof(struct node));
   if(ptr==NULL){
                  printf("\nCreated Failed \n");
                  return NULL;       
   }
   ptr->val=val;
   ptr->next=NULL;

   head=ptr;
   curr=ptr;

  return ptr;
}

main(){
   int  n,i;
   struct node *A=(struct node *)malloc(sizeof(struct node));
   struct node *B=(struct node *)malloc(sizeof(struct node));
   struct node *C=(struct node *)malloc(sizeof(struct node));
   struct node *new=(struct node *)malloc(sizeof(struct node));
   struct node *addEnd=(struct node *)malloc(sizeof(struct node));
   struct node *addAmong=(struct node *)malloc(sizeof(struct node));


   printf("\n-------- Welcome to Linked List Program -----------\n\n");

   do{

   printf("\nAdd to 'h'ead or 't'ail or 'b'ehind value:");   
   scanf("%c",&p); 
   fflush(stdin);

   switch(p)
{
    case 'h':
        printf("Enter value node:");
        scanf("%d",&v);
        fflush(stdin);
        if(head == NULL)
        {
                creatFirstNode(v);
                fflush(stdin);
        }
        else
        {
            curr=head;
            new->val=v;
            new->next=NULL;
            curr=new;
            curr->next=head;
            curr=curr->next;
            ("\ncreating list with headnode as [%d]\n",v);
            head=new;
            fflush(stdin);
        }
        //void printList();

   curr=head;
   printf("\n----Value in Liked list----\n");

   while(curr!=NULL){
              printf("[%d], ",curr->val); 
              curr=curr->next;  //change current node        
                    }
        break;

    case 't':
        printf("Enter value node tail:");
        scanf("%d",&v);



        curr=head;
        while(curr!=NULL){ //Seek for last node
                tail=curr;
                curr=curr->next; // shift to next node

            }

       addEnd->val=v;
       addEnd->next=NULL;
       tail->next=addEnd;        
        tail=new;
       fflush(stdin); 

        //void printList();.
        curr=head;
   printf("\n----Value in Liked list----\n");

   while(curr!=NULL){


              printf("[%d], ",curr->val); 
              curr=curr->next;  //change current node

          }

        break;

    case 'b':
        printf("Enter value node behind:");
        scanf("%d",&v);
        fflush(stdin);

        printf("Adding value [%d] in new node:",&v);
        printf("Add new node behind the value:");


        void printList();
        break;



        default:

        printf("\n     Invalid Input     ");
        getch();


}

}while(p != 'h' || p != 't' || p != 'b' );

getch();  
return 0;
 }

第六部分-----------------------------------------------------------------------------------------------------------------------------

#include<stdio.h>
#include<stdlib.h> 
#include<stdbool.h>

char p,j ;
int v;

struct node{
int val;
struct node *next;
};

struct node *head=NULL;
struct node *curr=NULL;
struct node *temp=NULL;
struct node *prev=NULL;
struct node *tail=NULL;
struct node *after=NULL;

struct node *creatFirstNode(int val){

   printf("\ncreating list with headnode as [%d]\n",val);
   struct node *ptr=(struct node *)malloc(sizeof(struct node));
   if(ptr==NULL){
                  printf("\nCreated Failed \n");
                  return NULL;       
   }
   ptr->val=val;
   ptr->next=NULL;

   head=ptr;
   curr=ptr;

  return ptr;
}

main(){
   int  n,i;
   struct node *A=(struct node *)malloc(sizeof(struct node));
   struct node *B=(struct node *)malloc(sizeof(struct node));
   struct node *C=(struct node *)malloc(sizeof(struct node));
   struct node *new=(struct node *)malloc(sizeof(struct node));
   struct node *addEnd=(struct node *)malloc(sizeof(struct node));
   struct node *addAmong=(struct node *)malloc(sizeof(struct node));


   printf("\n-------- Welcome to Linked List Program -----------\n\n");

   do{

   printf("\nAdd to 'h'ead or 't'ail or 'b'ehind value:");   
   scanf("%c",&p); 
   fflush(stdin);

   switch(p)
{
    case 'h':
        printf("Enter value node:");
        scanf("%d",&v);
        fflush(stdin);
        if(head == NULL)
        {
                creatFirstNode(v);
                fflush(stdin);
        }
        else
        {
            curr=head;
            new->val=v;
            new->next=NULL;
            curr=new;
            curr->next=head;
            curr=curr->next;
            ("\ncreating list with headnode as [%d]\n",v);
            head=new;
            fflush(stdin);
        }
        //void printList();

   curr=head;
   printf("\n----Value in Liked list----\n");

   while(curr!=NULL){
              printf("[%d], ",curr->val); 
              curr=curr->next;  //change current node        
                    }
        break;

    case 't':
        printf("Enter value node tail:");
        scanf("%d",&v);



        curr=head;
        while(curr!=NULL){ //Seek for last node
                tail=curr;
                curr=curr->next; // shift to next node

            }

       addEnd->val=v;
       addEnd->next=NULL;
       tail->next=addEnd;        
        tail=new;
       fflush(stdin); 

        //void printList();.
        curr=head;
   printf("\n----Value in Liked list----\n");

   while(curr!=NULL){


              printf("[%d], ",curr->val); 
              curr=curr->next;  //change current node

          }

        break;

    case 'b':
        printf("Enter value node behind:");
        scanf("%d",&v);
        fflush(stdin);

        printf("Adding value [%d] in new node:",&v);
        printf("Add new node behind the value:");


        void printList();
        break;



        default:

        printf("\n     Invalid Input     ");
        getch();


}

}while(p != 'h' || p != 't' || p != 'b' );

getch();  
return 0;
 }

范例

#include <stdio.h>
#include <stdlib.h>

typedef struct node {
    int val;
    struct node *next;
} Node;

Node *head, *tail;

Node *new_node(int val){
    struct node *ptr = malloc(sizeof(*ptr));
    if(ptr==NULL){
        perror("malloc:");
        printf("\nFailed to create a new node.\n");
        return NULL;
    }
    ptr->val  = val;
    ptr->next = NULL;

    return ptr;
}

Node *creatFirstNode(int val){
    return head = tail = new_node(val);
}

void printList(void){
    Node *np = head;

    printf("\n----Value in Liked list----\n");
    while(np){
        printf("[%d], ", np->val);
        np = np->next;
    }
    printf("NULL\n");
}

void freeList(void){
    while(head){
        Node *np = head->next;
        free(head);
        head = np;
    }
    tail = NULL;
}

int main(void){
    char cmd =' ';

    printf("\n-------- Welcome to Linked List Program -----------\n\n");

    do {
        int v = 0;

        printf("\nAdd to 'h'ead or 't'ail or 'b'ehind value or 'p'rint or 'q'uit:");   
        scanf(" %c", &cmd);

        switch(cmd){
        case 'h':
            printf("Enter value node head:");
            scanf("%d", &v);
            if(head == NULL){
                creatFirstNode(v);
            } else {
                Node *np = new_node(v);
                np->next = head;
                head = np;
            }
            break;

        case 't':
            printf("Enter value node tail:");
            scanf("%d", &v);
            if(head == NULL){
                creatFirstNode(v);
            } else {
                tail = tail->next = new_node(v);
            }
            break;

        case 'b':
            printf("Enter value node behind:");
            scanf("%d", &v);
            printf("\nUnimplemented yet.\n");
            break;

        case 'p':
            printList();
            break;
        case 'q':
            freeList();
            printf("\nBye!\n");
            break;

        default:
            printf("\n     Invalid Input     ");
        }
    }while(cmd != 'q' );

    return 0;
}

#包括
#包括
类型定义结构节点{
int-val；
结构节点*下一步；
}节点；
节点*头，*尾；
节点*新节点（int val）{
结构节点*ptr=malloc（sizeof（*ptr））；
如果（ptr==NULL）{
佩罗尔（“马洛克：”）；
printf（“\n未能创建新节点。\n”）；
返回NULL；
}
ptr->val=val；
ptr->next=NULL；
返回ptr；
}
节点*创建第一个节点（int val）{
返回头=尾=新节点（val）；
}
作废打印列表（作废）{
节点*np=头部；
printf（“\n----喜欢列表中的值----\n”）；
while（np）{
printf（“[%d]，”，np->val）；
np=np->next；
}
printf（“NULL\n”）；
}
void自由列表（void）{
while（head）{
节点*np=头部->下一步；
自由（头）；
水头=np；
}
tail=NULL；
}
内部主（空）{
char cmd=''；
printf（“\n------欢迎使用链表程序-----------\n\n”）；
做{
int v=0；
printf（“\n添加到'h'头或't'尾或'b'尾值或'p'打印或'q'uit:”）；
scanf（“%c”和&cmd）；
开关（cmd）{
案例“h”：
printf（“输入值节点头：”）；
scanf（“%d”和“&v”）；
if（head==NULL）{
第一节点（v）；
}否则{
Node*np=新的_节点（v）；
np->next=头部；
水头=np；
}
打破
案例“t”：
printf（“输入值节点尾部：”）；
scanf（“%d”和“&v”）；
if（head==NULL）{
第一节点（v）；
}否则{
tail=tail->next=new_节点（v）；
}
打破
案例“b”：
printf（“在后面输入值节点：”）；
scanf（“%d”和“&v”）；
printf（“\n尚未实现。\n”）；
打破
案例“p”：
打印列表（）；
打破
案例‘q’：
自由列表（）；
printf（“\n字节！\n”）；
打破
违约：
printf（“\n无效输入”）；
}
}while（cmd！=“q”）；
返回0；
}

我认为您还应该声明struct node*next=NULL；结构节点*before=NULL；：）如果没有这些声明，代码看起来不完整。：）哪里使用了节点A、B和C？：）1）分配每个节点。不要将其用作变量名，即使您使用的是C编译器，这也不是一个好的做法BTW

p！='h'| | p！='t'| | p！='b'

始终正确。感谢您的代码。不再是一个意外的循环！还有一个问题：我希望案例“b”添加节点并插入到我想要的任何节点后面。

案例“b”：

自己动手。嗯。。。好的，非常感谢兄弟！！：）当（np->val！=s）{prev=np；np=np->next；}prev->next=new_节点时，请执行一些错误；新建节点->下一个=np->下一个；}@我认为这显然是错误的。我认为你应该和我一起问新问题。