单链表

被自己蠢哭，找了几天的错误，后面才发现算法上出了问题，看来还是不行啊，自己写的算法检查不出错误。

#include<stdio.h> 
#include<stdlib.h>
int i;
typedef int  datatype;
typedef struct node{
	datatype data;
	struct node *next;//链接指针 
}Linknode;//*Linklist;//Linknode为结构体类型，Linklist为结构体类型指针 
/*
Linknode *Initial(Linknode *first)//用头插法创建链表 ，输出的值为逆序 
{
	int x;
	Linknode *s;
	printf("请输入数据：\n");
	scanf("%d",&x);
	first->next = NULL;
	while(x!=0){
		s = (Linknode*)malloc(sizeof(Linknode));
		if(s==NULL){
		  printf("存储分配错误");
		  exit(1);
		}
		s->data = x;
		s->next = first->next;
		first->next = s;
		scanf("%d",&x);
	}
	printf("初始化成功");
	return first;
}
*/
// 用尾插法创建链表
Linknode *Initial(Linknode *first) {
	int x;
	Linknode *s,*r;
	r = first;
	printf("请输入数据；\n");
	scanf("%d",&x);
	while(x!=0){
		s = (Linknode*)malloc(sizeof(Linknode));
		if(s==NULL){
		  printf("存储分配错误");
		  exit(1);
		  }
		s->data = x;
		r->next = s;
		r = s;
		scanf("%d",&x);
	}
	r->next = NULL;
	printf("初始化成功\n");
}

int length(Linknode *first){
	Linknode *p = first->next;
	int count = 0;
	while(p!=NULL){
		p = p->next;
		count++;
	}
	return count;
}

int search(Linknode *first,datatype x){
	Linknode *p = first->next;
	while(p!=NULL&&p->data!=x){
	     p=p->next;
	 } return p->data;
}

 Linknode *locate(Linknode *first,int i){
	if(i<0)
	printf("输入的参数不合理");
	Linknode *p = first;
	int k = 0;
	while(p!=NULL&&k<i){
		p = p->next;
		k++;
	}
	return p;
}

int Insert(Linknode *first,int i,int x){
	if(!first||i==1){
		Linknode *s = (Linknode *)malloc(sizeof(Linknode));
		if(!s){
			printf("存储分配错误\n");
			exit(1); 
		}
		s->data = x;
		 s->next= first->next;
		first->next= s;
	}
	else{
		Linknode *p = locate(first,i-1);
		if(p==NULL&&first==NULL){
			printf("无效的插入位置");
			return 0;
		}
	    else{
			Linknode *s = (Linknode *)malloc(sizeof(Linknode));
			if(!s){
				printf("存储分配错误\n");
				exit(1);
			}
			s->data = x;
			s->next = p->next;
			p->next = s;
		}
	}
	return 1;
}

int remove(Linknode *first,int i){
	Linknode *p = locate(first,i-1);
	if(p==NULL||p->next==NULL)
	return 0;
	Linknode *q = p->next;
	p->next = q->next; 
	free(q);
    return 1;
}

void show(Linknode *first)
{   
	Linknode *p = first->next;
	while(p != NULL)
	{
		printf("%d\n",p->data);
		p = p->next;
	}
}

void destoryLinknode(Linknode *first){
	Linknode *pre = first,*p = pre->next;
	while(p!=NULL){
		free(pre);
		pre = p;
		p = p->next;
	}
     free (pre);
     printf("单链表摧毁成功\n");
}


 void menu(Linknode *first)
{
  	system("cls");
  	printf("\n\n\n\n");
  	printf("\t\t|---------------单链表--------------------------|\n");
  	printf("\t\t|\t\t\t\t\t        |\n");
  	printf("\t\t|\t\t 1.单链表初始化 \t        |\n");
  	printf("\t\t|\t\t 2.计算单链表长度\t        |\n");
  	printf("\t\t|\t\t 3.插入元素\t                |\n");
  	printf("\t\t|\t\t 4.删除元素\t                |\n");
 	printf("\t\t|\t\t 5.元素定位\t                |\n");
 	printf("\t\t|\t\t 6.查找元素\t                |\n");
 	printf("\t\t|\t\t 7.输出链表元素 \t        |\n");
 	printf("\t\t|\t\t 8.单链表摧毁成功\t        |\n");
    printf("\t\t|\t\t\t\t\t        |\n");
  	printf("\t\t|-----------------------------------------------|\n\n");
  	printf("\t\t\t请选择(1-7):");
  	int n;
	scanf("%d",&n);
	switch(n){
		case 1:
			system("cls");
			Initial(first);
			printf("按任意键返回主菜单....");
			getchar();
			getchar();
			menu(first);
			break;
		case 2:
			system("cls");
			printf("链表长度为%d\n",length(first));
			printf("按任意键返回主菜单....");
			getchar();
			getchar();
			menu(first);
			break;
		case 3:
			system("cls");
			int x;
			printf("请输入插入的数据及位置\n");
			scanf("%d %d",&i,&x);
			if(Insert(first,i,x)){
				printf("插入成功\n");	
			}else{
				printf("插入失败\n");
			}
			printf("按任意键返回主菜单....");
			getchar();
			getchar();
			menu(first);
			break;
		case 4:
			system("cls");
			printf("请输入要删除的元素位置\n");
			scanf("%d",&i);
			if(remove(first,i)){
					printf("第%d个元素删除成功\n",i);
			}else
			   printf("输入的参数不合理");
			printf("按任意键返回主菜单....");
			getchar();
			getchar();
			menu(first);
			break;
		case 5:
			system("cls");
			printf("请输入要定位元素的位置\n");
			scanf("%d",&i);
			printf("该元素的地址为%d\n",locate(first,i));
			printf("按任意键返回主菜单....");
			getchar();
			getchar();
			menu(first);
			break;
		case 6:
			system("cls");
			printf("请输入要查找的元素的位置\n");
			scanf("%d",&i);
			printf("该元素为%d\n",search(first,i));
			printf("按任意键返回主菜单....");
			getchar();
			getchar();
			menu(first); 
			break;
		case 7:
		    system("cls");
		    show(first);
			printf("按任意键返回主菜单....");
			getchar();
			getchar();
			menu(first);
			break;
		case 8:
			system("cls");
			destoryLinknode(first);
			printf("按任意键退出程序....");
			getchar();
			getchar();
			break;
		}
}

int main(){
	Linknode *first = (Linknode*)malloc(sizeof(Linknode));
	if(first==NULL){
		  printf("存储分配错误");
		  exit(1);
		  }
	menu(first);
}