带头结点单链表基本操作参考代码

/*线性表抽象数据类型的带头结点单链表实现*/ #include <stdio.h>
#define OK 1
#define ERROR 0
#define TRUE 1
#define FALSE 0
#define OVERFLOW -2
#define MAXSIZE 100
#define NULL 0
typedef int status;
typedef int elemtype;
typedef struct lnode{
elemtype data;
struct lnode *next;
}lnode,*linklist;
/*初始化*/
status initlist(linklist *l){
*l=(linklist)malloc(sizeof(lnode));
if(*l) {(*l)->next=NULL;
return OK;
}
else return OVERFLOW;
}
/*销毁*/
status destroylist(linklist *l){
linklist p;
while(*l){
p=*l;
*l=(*l)->next;
free(p);
}
return OK;
}
/*置空*/
status clearlist(linklist *l){
linklist p,q;
p=(*l)->next;
(*l)->next=NULL;
while(p){
q=p;
p=p->next;
free(q);
}
return OK;
}
/*求单链表长度*/
int listlength(linklist l){
linklist p;
int i=0;
p=l->next;
while(p){
i++;
p=p->next;
}
return i;
}
/*单链表空否*/
status listempty(linklist l){
if(l->next) return FALSE;
else return TRUE;
}
/*查找*/
int locateelem(linklist l,elemtype e){
int i=0;
linklist p;
p=l->next;
while(p){
i++;
if (p->data==e) return i;
p=p->next;
}
return 0;
}
/*读第i个元素*/
status getelem(linklist l,int i,elemtype *e){
int j=1;
linklist p;
p=l->next;
while(p&&(j<i)){
j++;
p=p->next;
}
if (!p|| (j>i)) return ERROR;
*e=p->data;
return OK;
}
/*求前驱元素*/
status priorelem(linklist l,elemtype cur_e,elemtype *pre_e){
linklist p,q;
if(l->next&&(l->next->data==cur_e)) return ERROR;
q=l->next;
p=q->next;
while(p&&(p->data!=cur_e)){
q=p;
p=p->next;
}
if(!p) return ERROR;
*pre_e=q->data;
return OK;
}
/*求后继元素*/
status nextelem(linklist l,elemtype cur_e,elemtype *next_e){ linklist p;
p=l->next;
while(p&&(p->data!=cur_e))
p=p->next;
if(!p) return ERROR;
*next_e=p->next->data;
return OK;
}
/*在第i个位置插入元素e*/
status listinsert(linklist *l,int i,elemtype e){
int j=0;
linklist p,s;
p=*l;
while(p &&j<i-1){
j++;
p=p->next;
}
if(!p||(j>i-1)) return ERROR;
s= (linklist) malloc (sizeof(lnode));
s->data=e;
s->next=p->next;
p->next=s;
return OK;
}
/*删除第i个元素*/
status listdelete(linklist *l, int i, elemtype *e) {
linklist p,q;
int j;
p=*l;
j=0;
while ( p->next&& j<i-1){
p=p->next;
++j;
}
if (!(p->next)||j>i-1) return ERROR;
q=p->next;
p->next=q->next;
*e=q->data;
free(q);
return OK;
}
/*遍历单链表*/
status listtraverse(linklist l){
linklist p;
p=l->next;
while(p){
printf("%d ",p->data);
p=p->next;
}
printf("\n");
return OK;
}
/*尾插法建立顺序单链表*/
status listcreate(linklist *l){
linklist p,r,s;
elemtype e;
p=(linklist)malloc(sizeof(lnode));
r=p;
printf("input data(end by -1):");
scanf("%d",&e);
while(e!=-1){
s=(linklist)malloc(sizeof(lnode)); s->data=e;
r->next=s;
r=s;
scanf("%d",&e);
}
r->next=NULL;
*l=p;
return OK;
}
/*主函数*/
main(){
linklist la,lb,lc;
int i;
elemtype e,pre_e,next_e;
listcreate(&la);
listtraverse(la);
printf("the length of the list is %d\n",listlength(la));
printf("input i and e for insert:");
scanf("%d %d",&i,&e);
if(listinsert(&la,i,e)) listtraverse(la);
else printf("i is error!\n");
printf("input i :");
scanf("%d",&i);
getelem(la,i,&e);
printf("the element is %d ,",e);
priorelem(la,e,&pre_e);
nextelem(la,e,&next_e);
printf("prior is %d,",pre_e);
printf("next is %d\n",next_e);
listdelete(&la,i,&e);
listtraverse(la);
}。