#include <stdio.h>
2 #include <stdlib.h>
3 struct node;
4 typedef struct node *P;//意思是p 指向struct node的指针
5 typedef P list;//list 与 ptrtonode 同等意思，便于在下面的编程中理解
6 typedef P position;//意思是表示自引用结构中便于理解position是指向当前自身的指针
7 list makelist（list L）;//用于创造空链表，而其类型是list原因是makelist返回的是链表，而其类型是list
8 int isempty(list L);//判断是否为空链表，如果为空则返回true
9 int islast(position P,list L);//P是指向当前结点的指针，并且它的类型是position
10 position find (int x,list L);//在L链表中查找元素x
11 void delete(int x,list L);
12 void insert(int x,list L,position P);//P代表在结点，而x是代表在链表L中P结点前面插入x
13 position findprevious(int x,list L);
14 position header(list L);//不知道有什么用
15 position first(list L);//同上
16 position advance(position P);//同上
17 int retrieve(position P);//retrieve 意思是检索，恢复，其他同上
18 void printlist(list L);
19 struct node{
20 int data;
21 position next;
22 };
23
24 void main(){
25 list L;
26 int n;
27 L = makelist(list L);
28 printf("0 represent the element you want to look for in the list\n");
29 printf("1 represent the element you want to delete in the list\n");
30 printf("2 represent the element you want to insert in the list\n");
31 // scanf("%d",&n);
32 while (n == 0 || n == 1|| n == 2){
33 prinf("please input choose:\n");
34 scanf("%d",&n);
35 switch(n){
36 case '0':
37 printf("please input element you want to look for:\n");
38 int c;
39 position P;
40 scanf("%d",&c);
41 P= find(c,L);
42 printf("%s",P);
43 case '1':
44 printf("please input element you want to delete:\n");
45 int c;
46 scanf("%d",&c);
47 delete(c,L);
48 case '2':
49 printf("please input element you want to insert:\n");
50 int c;
51 position P;
52 scanf("%d,%s",&c,P);
53 insert(c,L,P);
54 default:
55 return "choosing error";
56 }
57 }
58 }
59
60 void printlist(list L){
61 position P;
62 P = header(L);
63 printf("the list is :\n");
64 if(P != NULL)
65 do {
66 printf("%d--",P -> data);
67 p = P -> next;
68 }while(P != NULL);
69 }
70
71 list makelist(list L){
72 position P;
73 P =L;
74 P -> next = NULL;
75 return P;
76 }
77
78 int isempty(list L){//return true if empty
79 return L-> next == NULL;
80 }
81
82 int islast(position P,list L){//ruturn true if P is the last position in list L.parametre(参数，系数) L is unused in this implementation（履行，实现）
83 return P -> next == NULL;//judge if the list is last ,if the list is null ,the return's value is true(1)
84 }
85
86 position find (int x,list L){//look for the present node x
87 position P;
88 p = L -> next;
89 while(P != NULL && P -> data != x)
90 P = P -> next;
91 return P;
92 }
93
94 void delete (int x,list L){
95 position P,tmpcell;
96 p = findprevious(x,L);
97 if(!islast(P,L)){
98 tmpcell = P -> next;
99 p -> next = tmpcell -> next;
100 free(tmpcell);
51 position P;
52 scanf("%d,%s",&c,P);
53 insert(c,L,P);
54 default:
55 return "choosing error";
56 }
57 }
58 }
59
60 void printlist(list L){
61 position P;
62 P = header(L);
63 printf("the list is :\n");
64 if(P != NULL)
65 do {
66 printf("%d--",P -> data);
67 p = P -> next;
68 }while(P != NULL);
69 }
70
71 list makelist(list L){
72 position P;
73 P =L;
74 P -> next = NULL;
75 return P;
76 }
77
78 int isempty(list L){//return true if empty
79 return L-> next == NULL;
80 }
81
82 int islast(position P,list L){//ruturn true if P is the last position in list L.parametre(参数，系数) L is unused in this implementation（履行，实现）
83 return P -> next == NULL;//judge if the list is last ,if the list is null ,the return's value is true(1)
84 }
85
86 position find (int x,list L){//look for the present node x
87 position P;
88 p = L -> next;
89 while(P != NULL && P -> data != x)
90 P = P -> next;
91 return P;
92 }
93
94 void delete (int x,list L){
95 position P,tmpcell;
96 p = findprevious(x,L);
97 if(!islast(P,L)){
98 tmpcell = P -> next;
99 p -> next = tmpcell -> next;
100 free(tmpcell);
101 printlist(L);
102 }
103 else
104 printf("the list is null\n");
105 }
106
107 position findprevious(x,L){//look for the next node x
108 position P;
109 P = L;
110 while(P -> next != NULL && P -> next -> data != x)
111 P = P -> next;
112 return P;
113 }
114
115 void insert(int x,list L,position P){
116 position tmpcell;
117 tmpcell = malloc(sizeof(struct node));
118 if(tmp == NULL)
119 printf("out of space");
120 tmpcell -> data = x;
121 tmpcell -> next = P -> next;
122 P -> next = tmpcell;
123 print(L);
124 }