编程练习题

 程序STUDENT *Create(STUDENT studs[],int n)。STUDENT是一个结构类型，包含姓名、成绩和指针域。studs数组中存储了n个STUDENT记录。create函数的功能是编写根据studs数组建立一个链表，链表中结点按成绩降序排列，函数返回链表头指针。

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

typedef struct student
{
char name[20];
int grade;
struct student * next;
}STUDENT;
typedef STUDENT * Link;

STUDENT *Create(STUDENT studs[], int n);
void create_empty_list(Link * head);
void is_malloc_ok(Link new_node);
void insert_node_sort(Link *head, Link new_node);
void display_list(Link head);

int main()
{
Link head = NULL;
int num;
int i;
Link studs = NULL;
printf("请输入数组大小:");
scanf("%d", &num);
studs = (Link)malloc(num*sizeof(STUDENT));
for (i = 0; i < num; i++)
{
printf("输入%d号记录的名字:", i);
scanf("%s", studs[i].name);
printf("输入%d号记录的成绩:", i);
scanf("%d", &studs[i].grade);
}
printf("输入的数据:\n");
printf("名字    成绩\n");
for (i = 0; i <num; i++)
{
printf("%s    %d\n", studs[i].name, studs[i].grade);
}
printf("降序排序后的数据:\n");
head = Create(studs,num);
display_list(head);
return 0;
}

void display_list(Link head)
{
Link p;
p = head;
printf("姓名    成绩\n");
while (p != NULL)
{
printf("%s    %d\n", p->name,p->grade);
p = p->next;
}
}

STUDENT *Create(STUDENT studs[], int n)
{
Link head = NULL;
Link new_node = NULL;
int i;
create_empty_list(&head);
for (i = 0; i < n; i++)
{
new_node = &studs[i];
insert_node_sort(&head, new_node);
}
return head;
}

void create_empty_list(Link *head)
{
*head = NULL;
}

void is_malloc_ok(Link new_node)
{
if (new_node == NULL)
{
printf("malloc error!\n");
exit(-1);
}
}

void insert_node_sort(Link *head, Link new_node)
{
Link p, front;
p = *head;
if (*head == NULL)
{
new_node->next = *head;
*head = new_node;
}
else
{
front = *head;
p = *head;
while (p != NULL&&new_node->grade <= p->grade)
{
front = p;
p = p->next;
}
if (p == *head)
{
new_node->next = *head;
*head = new_node;
}
else
{
new_node->next = p;
front->next = new_node;
}
}
}