I. data structure
How to store data
Well chosen data structures can improve efficiency
Data structure 1. Logical structure
One to many relationship between father and son
One to one relationship queuing
Many to many relationship route between two places
2. Storage structure
Location relationship of data storage
To store (an array) of data one by one
Chain storage

II. Linear table
In terms of logic, each element has its unique precursor and successor
The linear table of sequential storage is the sequential table
A linear list stored in chain is a linked list

III. sequence table
Main implementation mode: array / dynamic array
Sequentially stored linetype table
Data structure - > to manage data
Operate on data --- add, delete, find and modify

Attachment:
Static array (fixed size defined)
Cannot store data when array is full
Dynamic array
Array full -- > allocate new memory (request more space to store data)
Using malloc to request memory

The test code notes are as follows:

  1 #include<stdio.h>
  2 struct LIST  //Define structure
  3 {
  4     int arr[20];  //Array of data
  5     int size;  //How many elements can be stored in the array at most
  6     int len;  //How many elements have been stored in the array
  7 };
  8 
  9 //Initialization function
 10 void main(struct LIST*p)
 11 {
 12     //No data in the table at the beginning
 13     p->len = 0;
 14     p->size = 20; //Data that can be saved at most
 15 }
 16 
 17 //Add data
 18 void insert(struct LIST*p,int data)
 19 {
 20     //Insert end directly
 21     if (p->len < p->size)  //Description sequence table is not full
 22     {
 23         p->arr[p->len] = data;  //Judging according to the subscript of array len What we know is the next position of the last element
 24         p->len++;
 25         //Two lines are equivalent to p->arr[p->len++]=data;
 26     }
 27 }
 28 
 29 //Insert in middle insert in front
 30 void instert_middle(struct LIST*p, int data, int index)  //index Is the subscript inserted to the subscript location
 31 {
 32     if (p->len < p->size)  //Description sequence table is not full
 33     {
 34         if (index >= 0 && index < p->len)
 35         {
 36             //You can insert it in this position first
 37             //Make a place first
 38             for (int i = p->len; i>index; --i)
 39             {
 40                 p->arr[i] = p->arr[i - 1];  //Element moves back
 41             }
 42             p->arr[index] = data; //Insert in this position
 43             p->len++;  //An element is inserted, so let it add 1
 44         }
 45         else
 46         {
 47             p->arr[p->len++] = data;  //Otherwise insert the tail
 48         }
 49     }
 50 }
 51 
 52 //Find one by one
 53 int  search(struct  LIST*p, int data)
 54 {
 55     for (int i = 0; i < p->len; ++i)
 56     {
 57         if (data == p->arr[i])
 58         {
 59             return i;  //Eureka return subscript
 60         }
 61     }
 62     return -1;  //This location does not exist
 63 }
 64 
 65 //Modifying data
 66 void change(struct LIST*p,int data,int newData)
 67 {
 68     //Search by student's name
 69     for (int i = 0; i < p->len; ++i)
 70     {
 71         if (data == p->arr[i]);  //If you find it, modify it
 72         {
 73             p->arr[i] = newData;  //What is the character array of student name used for comparison strcmp  string.h
 74             break;  //If there is more than one same data, it should be modified and removed break
 75         }
 76     }
 77 }
 78 
 79 //Delete data delete is the overwrite cycle
 80 void dele(struct LIST*p, int data)
 81 {
 82     for (int i = 0; i < p -> len; ++i)
 83     {
 84         if (data == p->arr[i])  //Find location to start deletion
 85         {
 86             for (int j = i; j < p->len-1; ++j)  //Back to back
 87             {
 88                 p->arr[j] = p->arr[j + 1];
 89             }
 90             p->len--;
 91             break;
 92          }
 93      }
 94 }
 95 
 96 int main()
 97 {
 98 #if 0
 99     int x, y, z;
100     int k;
101     printf("%p,%p,%p,%p", &x, &y, &z, &k);
102 #endif
103 
104 #if 1
105 /*
106 Example:
107     Information student No. + name of the stored students
108 100 students in a class + students in a class + students in a class
109 150--70
110 Character array string
111 char arr[100]="hello world";//Array size array valid elements 11 characters
112 \0  Before valid data, after invalid data. This is only limited to character array
113 In the sequence table 1. How many data are there 2. How many data can be put
114 int brr[100]={1,2,34};
115 //You can put up to 100 pieces of data in 3 pieces
116 
117 Data duplication is not considered by default
118 */
119     struct LIST list; //Define a sequence table
120     init(&list);  //Call function initialization
121     insert(&list, 2);
122     instert_middle(&list, 3, 4);  //The inserted data is 3 inserted into the position with subscript 4
123 #endif
124     getchar();
125     return 0;
126 }

2019-03-30  09:17:07