list_again.c

C语言做菜单

//用结构体和指针实现动态链表程序
#include <stdio.h>
#include <malloc.h>

#define NULL 0
#define LEN sizeof(struct list)


struct list
{int num;
 struct list *next;
};
int n;

#ifdef MIAN
int main()
{
    int test=0;
    struct list *creat(void);
	int print(struct list *head);
	struct list *insert(struct list *head);
    struct list *del(struct list *head);
	int max_min(struct list *head);
	int back_list();
	int list_process();
	test=list_process();
    if(test)
		printf("success!\n");
	return(1);
}
#endif

struct list *creat(void)      //创建链表
{
	struct list *head,*p1,*p2;
	printf("Please input new record:\n");
    n=0;
    p1=p2=(struct list *)malloc(LEN);  //开辟新的空间
    scanf("%d",&p1->num);  
    head=NULL;
    while(p1->num!=0)
    {
	 n++;
	 if(n==1)        
         head=p1;
	 else
         p2->next=p1;
    p2=p1;
    p1=(struct list *)malloc(LEN);  //开辟新的空间
    scanf("%d",&p1->num);
    }
    p2->next=NULL;
    return(head);
}

/*
**打印链表(3)
*/

int print(struct list *head)    //输出链表
{
 struct list *p;
 p=head;
 if(head==NULL)
     printf("The list is null.\n");
 else
	 printf("There are %d records.\n",n);
	 do{
      printf("num is %d\n",p->num);
	  p=p->next;
	 }while(p!=NULL);
	 return(1);
}

/*
**插入一个结点(1)
*/
struct list *insert(struct list *head) //插入
{
 struct list *p0,*p1,*p2;
 p1=head;
 printf("input new list:\n");
 p0=(struct list *)malloc(sizeof(struct list));
 scanf("%d",&p0->num);
 if(head==NULL) 
 {head=p0;  p1->next=NULL;}
 else
 {
   while((p0->num>p1->num)&&(p1->next!=NULL))
   {p2=p1;  p1=p1->next;}
   if(p0->num<=p1->num)
	{if(head==p1) 
	     head=p0; 
     else
		 p2->next=p0;
     p0->next=p1;
    }
   else
   {p1->next=p0; p0->next=NULL;}
 }
 n++;
 return(head);
}

/*
**删除一个结点(2)
*/

struct list *del(struct list *head)  //有问题，但找不出来
{
   struct list *p1,*p2;
   	int num;
   printf("Please input del num:\n");
   scanf("%d",&num);
   p1=head;
   if(head==NULL)
	   printf("The list is null.\n");
   while(num!=p1->num&&p1->next!=NULL)
   {p2=p1;   p1=p1->next;}
	   if(num==p1->num)
	   {if(p1==head)
           head=p1->next;
        else
           p2->next=p1->next;
		printf("delete:%d\n",num);
        n=n-1;
	   }
      else
		  printf("The num is not found.\n");
return(head);
}

/*
**返回链表中的最大与最小值(4)
*/
int max_min(struct list *head)
{
	struct list *p1,*p2;
	int max=0,min=0;
	p2=head;
	p1=head->next;
	while(max<p1->num&&p1->num!=NULL)
	{
		max=p1->num;
		p2=p1;
		p1=p1->next;
		
	}
	printf("max is %d:\n",max);
	p2=head;
	p1=head->next;
	while(min>p1->num&&p1->num!=NULL)
	{
		min=p1->num;
		p2=p1;
		p1=p1->next;
	}
	printf("min is %d:\n",min);
	return(1);
}

/*
**返回上层菜单（5）
*/
int back_list()
{
	return(1);
}

/*
**退出（0）
*/


int list_process()
{
	struct list *head,*t;
	int c,i,j;
	head=creat();
	do{
	i=j=0;
	printf("1.input a node\n");
    printf("2.delete a node\n");
    printf("3.print the list\n");
	printf("4.return the max&min\n");
	printf("5.back_list\n");
	printf("0.exit\n");
	printf("please choose:\n");
	scanf("%d",&c);
	switch(c)
	{
	case 1: i=(int)insert(head); break;
	case 2: i=(int)del(head); break;
	case 3: i=print(head); break;
	case 4: i=max_min(head); break;
	case 5: j=back_list();break;
	case 0: break;
	default:printf("you input a wrong number!\n");list_process();
	}
	}while(i);
	if(j)
		return(1);
}