struct student

{

long num;

float score;

struct student *next;

};

注意：只是定义了一个struct student类型，并未实际分配存储空间。只有定义了变量才分配内存单元。

#include<iostream>

using namespace std;

int main() {

    struct student a,b,c,*head,*p;

    a.num = 99101;

    a.score = 89.5;

    b.num = 99103;

    b.score = 90;

    c.num = 99107;

    c.score = 85;        /*对结点的num和score成员赋值*/

    head = &a;        /*将结点a的起始地址赋给头指针head*/

    a.next = &b;        /*将结点b的起始地址赋给a结点的next成员*/

    b.next = &c;        /*将结点c的起始地址赋给b结点的next成员*/

    c.next = NULL;    /*c结点的next成员不存放其他结点地址*/

    p = head;        /*使p指针指向a结点*/

    do {

        cout<<p->num<<" "<<p->score;    /*输出p指向的结点的数据*/

        p=p->next;    /*使p指向下一结点*/

    } while (p!=NULL);    /*输出完c结点后p的值为NULL*/

    return 0;

}

/* Program 11.4   Daisy chaining the horses */

#include <stdio.h>

#include <ctype.h>

#include <stdlib.h>

int main(void)

{

  struct horse                        /* Structure declaration       */

  {

    int age;

    int height;

    char name[20];

    char father[20];

    char mother[20];

    struct horse *next;               /* Pointer to next structure   */

  };

  struct horse *first = NULL;         /* Pointer to first horse      */

  struct horse *current = NULL;       /* Pointer to current horse    */

  struct horse *previous = NULL;      /* Pointer to previous horse   */

  char test = '\0';                   /* Test value for ending input */

  for( ; ; )

  {

    printf("\nDo you want to enter details of a%s horse (Y or N)? ",

                                       first != NULL?"nother " : "" );

    scanf(" %c", &test );

    if(tolower(test) == 'n')

      break;

    /* Allocate memory for a structure */

    current = (struct horse*) malloc(sizeof(struct horse));

    if(first == NULL)

      first = current;                /* Set pointer to first horse  */

    if(previous != NULL)

      previous -> next = current; /* Set next pointer for previous horse */

    printf("\nEnter the name of the horse: ");

    scanf("%s", current -> name);     /* Read the horse's name       */

    printf("\nHow old is %s? ", current -> name);

    scanf("%d", &current -> age);     /* Read the horse's age        */

    printf("\nHow high is %s ( in hands )? ", current -> name );

    scanf("%d", &current -> height);  /* Read the horse's height     */

    printf("\nWho is %s's father? ", current -> name);

    scanf("%s", current -> father);   /* Get the father's name       */

    printf("\nWho is %s's mother? ", current -> name);

    scanf("%s", current -> mother);   /* Get the mother's name       */

    current->next = NULL;             /* In case it's the last...    */

    previous = current;               /* Save address of last horse  */

  }

  /* Now tell them what we know. */

  current = first;                    /* Start at the beginning      */

  while (current != NULL)      /* As long as we have a valid pointer */

  { /* Output the data*/

    printf("\n\n%s is %d years old, %d hands high,",

                       current->name, current->age, current->height);

    printf(" and has %s and %s as parents.", current->father,

                                               current->mother);

    previous = current;    /* Save the pointer so we can free memory */

    current = current->next;          /* Get the pointer to the next */

    free(previous);                   /* Free memory for the old one */

  }

  return 0;

}

/* Program 11.5 Daisy chaining the horses both ways */

#include <stdio.h>

#include <ctype.h>

#include <stdlib.h>

int main(void)

{

  struct horse                        /* Structure declaration       */

  {

    int age;

    int height;

    char name[20];

    char father[20];

    char mother[20];

    struct horse *next;             /* Pointer to next structure     */

    struct horse *previous;         /* Pointer to previous structure */

  };

  struct horse *first = NULL;         /* Pointer to first horse      */

  struct horse *current = NULL;       /* Pointer to current horse    */

  struct horse *last = NULL;          /* Pointer to previous horse   */

  char test = '\0';                   /* Test value for ending input */

  for( ; ; )

  {

    printf("\nDo you want to enter details of a%s horse (Y or N)? ",

                                        first == NULL?"nother " : "");

    scanf(" %c", &test );

    if(tolower(test) == 'n')

      break;

    /* Allocate memory for each new horse structure */

    current = (struct horse*)malloc(sizeof(struct horse));

    if( first == NULL )

    {

      first = current;                /* Set pointer to first horse  */

     current->previous = NULL;

    }

    else

    {

      last->next = current;    /* Set next address for previous horse */

      current->previous = last; /* Previous address for current horse */

    }

    printf("\nEnter the name of the horse: ");

    scanf("%s", current -> name );    /* Read the horse's name   */

    printf("\nHow old is %s? ", current -> name);

    scanf("%d", &current -> age);     /* Read the horse's age    */

    printf("\nHow high is %s ( in hands )? ", current -> name);

    scanf("%d", &current -> height);  /* Read the horse's height */

    printf("\nWho is %s's father? ", current -> name);

    scanf("%s", current -> father);   /* Get the father's name   */

    printf("\nWho is %s's mother? ", current -> name);

    scanf("%s", current -> mother);   /* Get the mother's name   */

    current -> next = NULL;      /* In case it's the last horse..*/

    last = current;              /* Save address of last horse   */

  }

  /* Now tell them what we know. */

  while(current != NULL)         /* Output horse data in reverse order */

  {

    printf("\n\n%s is %d years old, %d hands high,",

               current->name, current->age, current->height);

    printf(" and has %s and %s as parents.", current->father,

                                            current->mother);

    last = current;       /* Save pointer to enable memory to be freed */

    current = current->previous; /* current points to previous in list */

    free(last);                 /* Free memory for the horse we output */

  }

  return 0;

}