【数据结构】 双循环链表代码演示

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

typedef struct Data
{
Data *prior;    // 前驱指针
Data *next;     // 后继指针
int elem;       // 数据元素
}DoubleLinked,*PDoubleLinked;

void DisDoubleLinked(PDoubleLinked L);
void InsertDoubleLinked(PDoubleLinked L,int index,int elem);
void DeleteDoubleLinked(PDoubleLinked L,int index);
void ModifyDoubleLinked(PDoubleLinked L,int index,int elem);

void main()
{
PDoubleLinked L,P,Q;
int size = 0;

/**先初始化在使用*/
L = (PDoubleLinked)malloc(sizeof(DoubleLinked));

// 两种策略
// 一  用到的时候再申请
// 二  先申请 一大段 不够的时候再申请
P = L;
L->prior = NULL;

printf("请输入双链表的大小：");
scanf("%d",&size);

while (size-- != 0)
{
P->next = (PDoubleLinked)malloc(sizeof(DoubleLinked));
Q = P;
P = P->next;
P->prior = Q;
P->next = NULL;
P->elem = size*2+1;
}
P->next = L;
L->prior = P;    // 循环表头

// 显示双链表
DisDoubleLinked(L);
// 增
InsertDoubleLinked(L,2,23);
printf("\n");
DisDoubleLinked(L);
printf("\n");
// 删
DeleteDoubleLinked(L,3);
DisDoubleLinked(L);
printf("\n");
// 改
ModifyDoubleLinked(L,3,521);
DisDoubleLinked(L);
printf("\n");
}

void DisDoubleLinked(PDoubleLinked L)
{
PDoubleLinked P = L->next;

while (P != L)   // P ！= L 的时候循环进行
{
printf("%d\t",P->elem);
P = P->next;
}
}

void InsertDoubleLinked(PDoubleLinked L,int index,int elem)
{
PDoubleLinked P = L;
PDoubleLinked T;
PDoubleLinked Q = (PDoubleLinked)malloc(sizeof(DoubleLinked));
Q->elem = elem;

while (--index != 0)
{
P = P->next;
}
T = P->next;

Q->prior = P;
Q->next = T;

P->next = Q;
Q->next = T;
}

void DeleteDoubleLinked(PDoubleLinked L,int index)
{
PDoubleLinked P = L;
PDoubleLinked Q;

while (--index != 0)
{
P = P->next;
}

Q = P->next;
P->next = Q->next;
Q->next->prior = P;
free(Q);
}

void ModifyDoubleLinked(PDoubleLinked L,int index,int elem)
{
PDoubleLinked P = L;

while (index-- != 0)
{
P = P->next;
}

P->elem = elem;
}