数据结构:不带头结点的单链表

不带头结点的单链表实现

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

#define OK 1
#define ERROR 0
#define null NULL 
typedef int Elemtype;
typedef struct LNode{
	Elemtype data;
	struct LNode* next; 
};

typedef struct LNode Lnode;
typedef struct LNode *LinkList; 
 
bool InitList(LinkList L){
	L=null;
	return true;
} 

bool Empty(LinkList L){
	return (L==null);
}

int CreateFromHead(LinkList L){
	node *s,*r;
	int flag=1;
	Elemtype ch;
	while(flag){
		ch=scanf("%d",&ch);
		if(ch!=9999){
			s=(node*)malloc(sizeof(node));
			if(s==null){
				return ERROR;
			} 
			r=L;
			L=s; 
			s->next=r;
		}
		else{
			break;
		}
	}
	return OK;
} 

int CreateFromTail(LinkList L){
	node *r,*s;
	int flag;
	int number=1;
	Elemtype ch;
	while(flag){
		ch=scanf("%d",&ch);
		if(ch!=9999){
			s=(node*)malloc(sizeof(node));
			if(s==null){
				return ERROR;
			}
			if(number==1){
				L=s;
				r=L;
			}
			r->next=s;
			s->next=null;
			r=s;
		}
		else{
			r->next=null;
			break;
		}
	}
}

int GetElem(LinkList L,int i){
	node *p;
	int j=1;
	if(i<1){
		return ERROR;
	}
	p=L;
	while(L&&j<i){
		p=p->next;
		j++;
	}
	if(L==null){
		return ERROR;
	}
	return OK;
}

int LocaElem(LinkList L,Elemtype e){
	node *p;
	p=L;
	while(p&&(p->data!=e)){
		p=p->next;
	}
	if(p==null){
		return ERROR;
	}
	return OK;
}

int InsertElem(LinkList L,int i,Elemtype e){
	node *pre,r;
	int j=1;
	if(i<1){
		return ERROR;
	}	
	pre=L;
	while(pre&&j<i-1){
		pre=pre->next;
		j++;
	}
	if(pre==null){
		return ERROR;
	}
	r=(Lnode*)malloc(sizeof(Lnode));
	r->next=pre->next;
	pre->next=r;
	r->data=e;
	return OK;
}

int DelElem(LinkList L,int i){
	node *pre=L;
	int j=0;
	while(pre!=null&&j<i-1){
		pre=pre->next;
		j++;
	}
	if(pre==null){
		return ERROR;
	}
	if(pre->next==null){
		return ERROR;
	}
	node *Tem;
	Tem=pre->next;
	pre->next=Tem->next;
	free(Tem);
	return OK;
}

//链表逆序 参考头插法建表,注意此时移动的是L,L不断向前移动 
 
//main()
int main(int argc, char *argv[])
{
	LinkList L;// 
	 
	return 0;
}