원형 연결 리스트

#include<stdio.h> #include<stdlib.h> typedef int element; typedef struct node { element data; struct node * link ; }node; void error(char *message){ fprintf(stderr,"%s /n",message); exit(1); } node *create_node(element data, node * link){ node *new_node; new_node = (node *)malloc(sizeof(node)); if(new_node == NULL) error("MALLOC ERROR"); new_node -> data = data; new_node -> link = link; return (new_node); } void display(node * head){ node *p; if(head == NULL) return; p = head->link; do{ printf("%d->", p->data); p = p->link; }while(p != head); printf("%d->", p->data); } void insert_first(node **phead, node *new){ if( *phead == NULL){ *phead = new; new ->link = new; } else{ new->link= (*phead) -> link; (*phead) ->link = new; } } void insert_last(node **phead, node *new){ if(*phead == NULL){ *phead = new; new -> link = new; } else{ new -> link = (*phead) -> link; (*phead) -> link = new; *phead = new; } } int main(void){ node *p = NULL; // 20 -> 10-> 30; insert_first(&p,create_node(10,NULL)); insert_first(&p,create_node(20,NULL)); insert_last(&p,create_node(30,NULL)); display(p); return 0; }