一个使用递归在字符链表(使用随机数生成器插入字符)中搜索元素的程序

Question

有人能帮我如何实现这个吗??我无法创建一个逻辑来做到这一点。如何插入随机字符，然后如何通过它递归搜索?这就是我到目前为止所做的……

#include<stdio.h>
#include<conio.h>
#include<alloc.h>
//-------------------------------------------------
struct node
{
    char data;
    struct node *next;
}*start=NULL;
//------------------------------------------------------------
void create()
{
    char ch;
    do
    {
        struct node *new_node,*current;
        new_node=(struct node *)malloc(sizeof(struct node));
        /*I want random characters inserted here*/
        new_node->next=NULL;
        if(start==NULL)
        {
            start=new_node;
            current=new_node;
        }
        else
        {
            current->next=new_node;
            current=new_node;
        }
        printf("nDo you want to creat another : ");
        ch=getche();
    }while(ch!='n');
}

void main()
{
    create();
    display();
}

Answer 1

我已经注释了所做的更改。您需要具体化您的链表概念。希望能有所帮助

  `#include<stdio.h>
   #include<conio.h>
   #include<alloc.h>
   //-------------------------------------------------
   struct node
   {
    char data;
    struct node *next;
   }*start=NULL;
   //------------------------------------------------------------
 static struct node *new_node,*current;  //declared these static outside the create funtion
  void create()
    {
     char ch;
     do
      {

       new_node=(struct node *)malloc(sizeof(struct node));
        /*I want random characters inserted here*/
       new_node->next=NULL;
        printf("Enter the data in the nodes: "); //asking you to enter data in nodes
        scanf(" %c",&(new_node->data));    //entering data in the linked list node
       if(start==NULL)
        {
         start=new_node;
         current=new_node;
        }
       else
        {
        current->next=new_node;
        current=new_node;
        }
    printf("nDo you want to creat another : ");
    ch=getche();
}while(ch!='n');
}
void display()   //display function defined here
    {
      struct node *arbitrary_pointer;
      arbitrary_pointer=start;
      while(arbitrary_pointer!=NULL)
       {
         printf(" %c",arbitrary_pointer->data);
         arbitrary_pointer=arbitrary_pointer->next;
       }
    }
  int main()              //changed return type of main function from void to int
   {
    create();
    display();
    return 0;
   }

"

Answer 2

将此程序作为您的程序的模板。这个程序提供了在列表中搜索字符的递归方法。

#include <stdlib.h>
#include <stdio.h>
#include <time.h>
struct Node
{
    char data;
    struct Node *next;
};
void insert_front( struct Node **head, char c )
{
    struct Node *tmp = malloc( sizeof( struct Node ) );
    if ( tmp != NULL )
    {               
        tmp->data = c;
        tmp->next = *head;
        *head = tmp;
    }
}
void free_list( struct Node *head )
{
    while ( head != NULL )
    {
        struct Node *tmp = head;
        head = head->next;
        free( tmp );
    }
}
void display_list( struct Node *head )
{
    for ( ; head != NULL; head = head->next ) printf( "%c ", head->data );
}
struct Node * find_node( struct Node *head, char c )
{
    return head == NULL || head->data == c ? head : find_node( head->next, c );
}
int main( void )
{
    const char alphabet[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
    struct Node *head = NULL;
    srand( ( unsigned int )time( NULL ) );
    const size_t N = 10;
    for ( size_t i = 0; i < N; i++ )
    {
        insert_front( &head, alphabet[rand() % ( sizeof( alphabet ) - 1 )] );
    }
    display_list( head );
    printf( "n" );
    while ( 1 )
    {
        struct Node *node;
        char c = '@';
        printf( "Enter letter to search in the list (@-exit): " );
        scanf( " %c", &c );
        if ( c == '@' ) break;
        node = find_node( head, c );
        if ( node != NULL ) printf( "Letter %c is present in the listn", c );
        else printf( "Letter %c is not present in the listn", c );
    }
    free_list( head );
}    

如果要输入例如

A E I O U @

则程序输出可能看起来像

W H T C E H N J F N 
Enter letter to search in the list (@-exit): A
Letter A is not present in the list
Enter letter to search in the list (@-exit): E
Letter E is present in the list
Enter letter to search in the list (@-exit): I
Letter I is not present in the list
Enter letter to search in the list (@-exit): O
Letter O is not present in the list
Enter letter to search in the list (@-exit): U
Letter U is not present in the list
Enter letter to search in the list (@-exit): @

函数find_node返回一个节点。因此，您可以使用它来查找一个字母的所有出现情况。

例如

size_t count = 0;
struct Node *node = head;
char c = 'A';
while ( ( node = find_node( node, c ) ) != NULL )
{
    ++count;
    node = node->next;
}
printf( "There are %zu letters %c in the listn", count, c );

顺便说一下，在俄罗斯还有一个名字Katherine:)