After we learn the structure, we can try to realize the production of the address book. If you don't know much about the structure, please visit this article first, which will be beneficial to the next study. [Custom Type] Take you into the structure, enumeration, union_Xiaowang Xuecode Blog-CSDN Blog
Table of contents
2. How to write the main body of the address book?
2. Initialize the address book
3. Delete designated personnel
4. Find the information of the designated person
5. Change the information of the designated person
6. Print address book personnel information
3. Modify the add personnel function
foreword
The address book is a simple program. Next, we use C language to implement static and dynamic address books. Let's first understand what is static?
Static address book: The size of the address book that can store people is fixed, which may be wasted or not enough
Dynamic address book: It can realize dynamic expansion, if it is not enough, expand the capacity, which saves time and space and is more convenient
1. Contacts
First of all, we should know what functions the address book should have
1. Additions, deletions, checks and changes must have
2. Close the address book
3. Sort the people in the address book
2. Static address book
Dynamic than static only needs to modify part of the content, let's first explain how to make a static address book
1. What function to complete
Graphic:
2. How to write the main body of the address book?
Use the form of the menu, use the test function outside the main function, and use the do while and switch functions in the test to realize the basic framework of the address book. The specific code is as follows.
Code demo:
//这边进行主要的通讯录流程操作
void menu() {
printf("***********************************************\n");
printf("****** 1.add 2.del ******\n");
printf("****** 3.search 4.change ******\n");
printf("****** 5.show 6.sort ******\n");
printf("****** 0.exit ******\n");
printf("***********************************************\n");
}
void test() {
int input = 0;
int pos = 0;
Contact pc;
//Contact pc={0};
//当然可以这样初始化，但是不一定后来初始化都这样，所以有InitContact（）
InitContact(&pc);
do {
menu();
//打印选择菜单
printf("请选择：>");
scanf("%d", &input);
switch (input) {
case 1:
addContact(&pc);
break;
case 2:
delContact(&pc);
break;
case 3:
searchContact(&pc);
break;
case 4:
changeContact(&pc);
break;
case 5:
showContact(&pc);
break;
case 6:
sortContact(&pc);
break;
case 0:
printf("退出通讯录\n");
break;
default:
break;
}
} while (input);
}
int main()
{
test();
return 0;
}
3. Gradually complete various functions
The implementation of functions such as initialization, addition, deletion, modification, and sorting, we put them in the Contact.c file for implementation
1. Realization of structure
code show as below:
#define MAX 100
#define NAME_MAX 20
#define SEX_MAX 5
#define ADDR_MAX 20
#define TELE_MAX 12
//下面两个define是用于动态通讯录的
#define MAX1 3 //表示第一次容积是多少
#define MAX2 2 //表示一次扩容多少
//构建通讯录所需的结构体
typedef struct PeopleInfo {
char name[NAME_MAX];//姓名
int age;//年龄
char sex[NAME_MAX];//性别
char addr[ADDR_MAX];//地址
char tele[TELE_MAX];//电话号码
}PeopleInfo;
//这是静态通讯录 就是data这个数组是固定死的MAX
typedef struct Contact {
PeopleInfo data[MAX];//表示存储的通讯录最大人员数
int sz;//表示当前Contact通讯录人员个数
}Contact;
2. Initialize the address book
code show as below:
//这是静态初始化
void InitContact(Contact* pc) {
//进行初始化的时候，我们当然可以直接
pc->sz = 0;
memset(pc->data, 0, sizeof(pc->data));
//memset 函数 这样的话，从data这个数组的地址开始 sizeof(pc->data)个字节，都赋值为0
}
The memset memory management function is used to initialize the pc->data array to 0, and sz represents the number of personnel, which is also 0
3. Add people
code show as below:
//静态通讯录
void addContact(Contact* pc) {
assert(pc);//断言
if (pc->sz == MAX) { //判满，满了无法添加
printf("通讯录已满，无法添加\n");
return;
}
printf("请输入名字:>");
scanf("%s", pc->data[pc->sz].name);
printf("请输入年龄:>");
scanf("%d", &(pc->data[pc->sz].age));
printf("请输入性别:>");
scanf("%s", pc->data[pc->sz].sex);
printf("请输入地址:>");
scanf("%s", pc->data[pc->sz].addr);
printf("请输入电话:>");
scanf("%s", pc->data[pc->sz].tele);
printf("添加完成,请继续操作\n");
//添加完一个就sz++，表示有一个人员加入通讯录中
pc->sz++;
}3. Delete designated personnel
code show as below:
void delContact(Contact* pc) {
assert(pc);
printf("请选择删除的目标:>");
if (pc->sz == 0) {
return;
}
//删除的话只需要找到对应的要删除的数据，比如以名字为准，先找到，然后再讲其后面的元素覆盖前面的
int pos = searchContact(pc);
//换位置
if (pos == -1) {
printf("没有查找到该成员\n");
return;
}
for (int i = pos; i < pc->sz - 1; i++) {
pc->data[i] = pc->data[i + 1];
}
pc->sz--;//直接--不用管换位置之后最后一个数字的问题
printf("删除完成\n");
}
You can delete the person with the specified name, and of course you can make some improvements yourself. This is a relatively simple and easy-to-understand address book.
4. Find the information of the designated person
code show as below:
int searchContact(Contact* pc) {
assert(pc);//断言
char name[20];
int pos = -1; //pos等于-1是因为 如果找不到一样的姓名，就返回-1，表示没有
scanf("%s", name);
//查询
for (int i = 0; i < pc->sz; i++) {
if (strcmp(pc->data[i].name, name) == 0) {
pos = i; //使用strcmp函数，进行比较
}
}
return pos;
}
The strcmp function is used. If you don’t understand it, you can go to the link below to visit it.
5. Change the information of the designated person
code show as below:
int searchContact(Contact* pc) {
assert(pc);
char name[20];
int pos = -1;
scanf("%s", name);
//查询
for (int i = 0; i < pc->sz; i++) {
if (strcmp(pc->data[i].name, name) == 0) {
pos = i;
}
}
return pos;
}
//协助查找函数被，找到被查改人员在data数组的下标位置，再进行修改
void changeContact(Contact* pc) {
assert(pc);
//先找到
int pos = searchContact(pc);
printf("请输入名字:>");
scanf("%s", pc->data[pos].name);
printf("请输入年龄:>");
scanf("%d", &(pc->data[pos].age));
printf("请输入性别:>");
scanf("%s", pc->data[pos].sex);
printf("请输入地址:>");
scanf("%s", pc->data[pos].addr);
printf("请输入电话:>");
scanf("%s", pc->data[pos].tele);
printf("更改完成, 请继续操作\n");
}
Assist in the search function, find the subscript position of the inspected person in the data array, and then modify it.
6. Print address book personnel information
code show as below:
void showContact(Contact* pc) {
assert(pc);
if (pc->sz == 0) {
return;
}//可以有可无
printf("%-20s\t%-5s\t%-5s\t%-20s\t%-12s\n", "姓名", "年龄", "性别", "地址", "电话");
for (int i = 0; i < pc->sz; i++) {
printf("%-20s\t%-5d\t%-5s\t%-20s\t%-12s\n", pc->data[i].name, pc->data[i].age, pc->data[i].sex, pc->data[i].addr, pc->data[i].tele);
}
printf("打印完成\n");
}
For the explanation of %-20s \ t in printf, - means left alignment, 20 means 20 positions of this string, keep left-aligned printing, \t is a word table character, which is for more beautiful appearance and makes all data alignment
7. Sort contacts
There are many basis for sorting, here we are sorting according to the size of the name, use the function strcmp, in fact, you can also use the qsort function to sort
code show as below:
void sortContact(Contact* pc) {
assert(pc);
if (pc->sz == 0) {
printf("通讯录中暂无元素\n");
return;
}
Contact s = { 0 };
for (int i = 0; i < pc->sz-1; i++) {
for (int j = i; j < pc->sz-1; j++) {
if (strcmp(pc->data[j].name, pc->data[j + 1].name)==1) {
s.data[j] = pc->data[j];
pc->data[j] = pc->data[j + 1];
pc->data[j + 1] = s.data[j];
}
}
}
}
The strcmp function combined with bubble sorting is used, so that the qsort function can also be used, and the usage method can refer to
[Advanced C Language] Advanced Pointers (Part 2) - Xiaowang Xuecode Blog - CSDN Blog
The qsort function code is as follows:
int compare(const void* e1, const void* e2) {
return *((int*)e1) - *((int*)e2);
}
void sort(Contact*pc) {
qsort(pc->data, pc->sz, sizeof(pc->data[0]), compare);
}3. Dynamic address book
Compared with the static address book, the dynamic address book has been changed mainly in structure, initialization, and adding members.
1. Modify the structure
code show as below:
//构建通讯录所需的结构体
typedef struct PeopleInfo {
char name[NAME_MAX];//姓名
int age;//年龄
char sex[NAME_MAX];//性别
char addr[ADDR_MAX];//地址
char tele[TELE_MAX];//电话号码
}PeopleInfo;
//实现动态通讯录
typedef struct Contact {
PeopleInfo *data;//表示存储的通讯录最大人员数
int sz;//表示当前Contact通讯录人员个数
int capacity; //表示当前容量 作为扩容的依据
}Contact;The data array is changed into a pointer form, the capacity of the address book is no longer fixed, and the capacity can be expanded appropriately
2. Change initialization
Use the malloc function for memory application and initialization
code show as below:
//这是动态通讯录的初始化
void InitContact(Contact* pc) {
//进行初始化的时候，我们当然可以直接
assert(pc);//断言
pc->sz = 0;
PeopleInfo *ptr=(PeopleInfo*)calloc(MAX1,sizeof(PeopleInfo));
if (ptr == NULL) {
perror("malloc::data");
return;
}
pc->data = ptr;
pc->capacity=MAX1;
}Apply for data space, MAX1 represents the initial data capacity
3. Modify the add personnel function
To implement the capacity expansion mechanism, if sz and capacity are equal, it means that the number of personnel is equal to the capacity, and no more personnel can be added. At this time, the check_capacity function is required to check whether it is full and expand the capacity
code show as below:
//动态通讯录
void check_capacity(Contact* pc) {
PeopleInfo* ptr = (PeopleInfo*)realloc(pc->data, sizeof(PeopleInfo)*(pc->capacity+MAX2));
if (ptr == NULL) {
perror("check_capacity");
return;
}
pc->data = ptr;
pc->capacity = pc->capacity + MAX2;
}
void addContact(Contact* pc) {
assert(pc);
if (pc->sz == pc->capacity) {
//使用realloc函数 进行扩容
check_capacity(pc);
printf("扩容完成\n");
}
printf("请输入名字:>");
scanf("%s", pc->data[pc->sz].name);
printf("请输入年龄:>");
scanf("%d", &(pc->data[pc->sz].age));
printf("请输入性别:>");
scanf("%s", pc->data[pc->sz].sex);
printf("请输入地址:>");
scanf("%s", pc->data[pc->sz].addr);
printf("请输入电话:>");
scanf("%s", pc->data[pc->sz].tele);
printf("添加完成,请继续操作\n");
pc->sz++;
}The realloc function is used for capacity expansion
4. Overall address book code
1. Static address book
There are three kinds of files, test.c Contact.c Contact.h, which are framework, implementation, header file declaration, three functions
1.test.c file
#define _CRT_SECURE_NO_WARNINGS
#include"Contact.h"
//这边进行主要的通讯录流程操作
void menu() {
printf("***********************************************\n");
printf("****** 1.add 2.del ******\n");
printf("****** 3.search 4.change ******\n");
printf("****** 5.show 6.sort ******\n");
printf("****** 0.exit ******\n");
printf("***********************************************\n");
}
void test() {
//打印选择菜单
int input = 0;
int pos = 0;
Contact pc;
//Contact pc={0};
//当然可以这样初始化，但是不一定后来初始化都这样，所以有InitContact（）
InitContact(&pc);
do {
menu();
printf("请选择：>");
scanf("%d", &input);
switch (input) {
case 1:
addContact(&pc);
break;
case 2:
delContact(&pc);
break;
case 3:
pos = searchContact(&pc);
if (pos == -1) {
printf("没有查找到该成员\n");
}
else {
printf("%-20s\t%-5d\t%-5s\t%-20s\t%-12s\n", pc.data[pos].name, pc.data[pos].age, pc.data[pos].sex, pc.data[pos].addr, pc.data[pos].tele);
}
break;
case 4:
changeContact(&pc);
break;
case 5:
showContact(&pc);
break;
case 6:
sort(&pc);
break;
case 0:
printf("退出通讯录\n");
break;
default:
break;
}
} while (input);
}
int main()
{
test();
return 0;
}
2.Contact.c
#define _CRT_SECURE_NO_WARNINGS
#include"Contact.h"
//用来实现头文件的代码
//
这是静态初始化
void InitContact(Contact* pc) {
//进行初始化的时候，我们当然可以直接
pc->sz = 0;
memset(pc->data, 0, sizeof(pc->data));
//memset 函数 这样的话，从data这个数组的地址开始 sizeof(pc->data)个字节，都赋值为0
}
静态通讯录
void addContact(Contact* pc) {
assert(pc);
if (pc->sz == MAX) {
printf("通讯录已满，无法添加\n");
return;
}
printf("请输入名字:>");
scanf("%s", pc->data[pc->sz].name);
printf("请输入年龄:>");
scanf("%d", &(pc->data[pc->sz].age));
printf("请输入性别:>");
scanf("%s", pc->data[pc->sz].sex);
printf("请输入地址:>");
scanf("%s", pc->data[pc->sz].addr);
printf("请输入电话:>");
scanf("%s", pc->data[pc->sz].tele);
printf("添加完成,请继续操作\n");
pc->sz++;
}
void delContact(Contact* pc) {
assert(pc);
printf("请选择删除的目标:>");
if (pc->sz == 0) {
return;
}
//删除的话只需要找到对应的要删除的数据，比如以名字为准，先找到，然后再讲其后面的元素覆盖前面的
int pos = searchContact(pc);
//换位置
if (pos == -1) {
printf("没有查找到该成员\n");
return;
}
for (int i = pos; i < pc->sz - 1; i++) {
pc->data[i] = pc->data[i + 1];
}
pc->sz--;//直接--不用管换位置之后最后一个数字的问题
printf("删除完成\n");
}
int searchContact(Contact* pc) {
assert(pc);
char name[20];
int pos = -1;
scanf("%s", name);
//查询
for (int i = 0; i < pc->sz; i++) {
if (strcmp(pc->data[i].name, name) == 0) {
pos = i;
}
}
return pos;
}
void showContact(Contact* pc) {
assert(pc);
if (pc->sz == 0) {
return;
}//可以有可无
printf("%-20s\t%-5s\t%-5s\t%-20s\t%-12s\n", "姓名", "年龄", "性别", "地址", "电话");
for (int i = 0; i < pc->sz; i++) {
printf("%-20s\t%-5d\t%-5s\t%-20s\t%-12s\n", pc->data[i].name, pc->data[i].age, pc->data[i].sex, pc->data[i].addr, pc->data[i].tele);
}
printf("打印完成\n");
}
void changeContact(Contact* pc) {
assert(pc);
//先找到
int pos = searchContact(pc);
printf("请输入名字:>");
scanf("%s", pc->data[pos].name);
printf("请输入年龄:>");
scanf("%d", &(pc->data[pos].age));
printf("请输入性别:>");
scanf("%s", pc->data[pos].sex);
printf("请输入地址:>");
scanf("%s", pc->data[pos].addr);
printf("请输入电话:>");
scanf("%s", pc->data[pos].tele);
printf("更改完成, 请继续操作\n");
}
void sortContact(Contact* pc) {
assert(pc);
if (pc->sz == 0) {
printf("通讯录中暂无元素\n");
return;
}
Contact s;
InitContact(&s);
for (int i = 0; i < pc->sz-1; i++) {
for (int j = 0; j < pc->sz-1-i; j++) {
if (strcmp(pc->data[j].name, pc->data[j + 1].name)==1) {
s.data[j] = pc->data[j];
pc->data[j] = pc->data[j + 1];
pc->data[j + 1] = s.data[j];
}
}
}
}
int compare(const void* e1, const void* e2) {
return *((int*)e1) - *((int*)e2);
}
void sort(Contact*pc) {
qsort(pc->data, pc->sz, sizeof(pc->data[0]), compare);
}3.Contact.h
#define _CRT_SECURE_NO_WARNINGS
//Contact 实现通讯录 头文件
#include<stdio.h>
#include<string.h>
#include<assert.h>
#include<malloc.h>
#include<stdlib.h>
#include<search.h>
#define MAX 100
#define NAME_MAX 20
#define SEX_MAX 5
#define ADDR_MAX 20
#define TELE_MAX 12
//下面两个define是用于动态通讯录的
#define MAX1 3 //表示第一次容积是多少
#define MAX2 2 //表示一次扩容多少
//构建通讯录所需的结构体
typedef struct PeopleInfo {
char name[NAME_MAX];//姓名
int age;//年龄
char sex[NAME_MAX];//性别
char addr[ADDR_MAX];//地址
char tele[TELE_MAX];//电话号码
}PeopleInfo;
//这是静态通讯录 就是data这个数组是固定死的MAX
typedef struct Contact {
PeopleInfo data[MAX];//表示存储的通讯录最大人员数
int sz;//表示当前Contact通讯录人员个数
}Contact;
//初始化通讯录
void InitContact(Contact* pc);
//添加通讯录的信息
void addContact(Contact* pc);
//删除通讯录中的信息
void delContact(Contact* pc);
//查找通讯录成员信息
int searchContact(Contact* pc);
//打印
void showContact(Contact* pc);
//改变指定元素
void changeContact(Contact* pc);
//排序，按照名字排序
void sortContact(Contact* pc);2. Dynamic address book
1.test.c
#define _CRT_SECURE_NO_WARNINGS
#include"Contact.h"
//这边进行主要的通讯录流程操作
void menu() {
printf("***********************************************\n");
printf("****** 1.add 2.del ******\n");
printf("****** 3.search 4.change ******\n");
printf("****** 5.show 6.sort ******\n");
printf("****** 0.exit ******\n");
printf("***********************************************\n");
}
void test() {
//打印选择菜单
int input = 0;
int pos = 0;
Contact pc;
//Contact pc={0};
//当然可以这样初始化，但是不一定后来初始化都这样，所以有InitContact（）
InitContact(&pc);
do {
menu();
printf("请选择：>");
scanf("%d", &input);
switch (input) {
case 1:
addContact(&pc);
break;
case 2:
delContact(&pc);
break;
case 3:
pos = searchContact(&pc);
if (pos == -1) {
printf("没有查找到该成员\n");
}
else {
printf("%-20s\t%-5d\t%-5s\t%-20s\t%-12s\n", pc.data[pos].name, pc.data[pos].age, pc.data[pos].sex, pc.data[pos].addr, pc.data[pos].tele);
}
break;
case 4:
changeContact(&pc);
break;
case 5:
showContact(&pc);
break;
case 6:
sort(&pc);
break;
case 0:
printf("退出通讯录\n");
free(pc.data);
break;
default:
break;
}
} while (input);
}
int main()
{
test();
return 0;
}
2.Contact.c
#define _CRT_SECURE_NO_WARNINGS
#include"Contact.h"
//用来实现头文件的代码
//
//这是动态通讯录的初始化
void InitContact(Contact* pc) {
//进行初始化的时候，我们当然可以直接
assert(pc);//断言
pc->sz = 0;
PeopleInfo *ptr=(PeopleInfo*)calloc(MAX1,sizeof(PeopleInfo));
if (ptr == NULL) {
perror("malloc::data");
return;
}
pc->data = ptr;
pc->capacity=MAX1;
}
//动态通讯录
void check_capacity(Contact* pc) {
PeopleInfo* ptr = (PeopleInfo*)realloc(pc->data, sizeof(PeopleInfo)*(pc->capacity+MAX2));
if (ptr == NULL) {
perror("check_capacity");
return;
}
pc->data = ptr;
pc->capacity = pc->capacity + MAX2;
}
void addContact(Contact* pc) {
assert(pc);
if (pc->sz == pc->capacity) {
//使用realloc函数 进行扩容
check_capacity(pc);
printf("扩容完成\n");
}
printf("请输入名字:>");
scanf("%s", pc->data[pc->sz].name);
printf("请输入年龄:>");
scanf("%d", &(pc->data[pc->sz].age));
printf("请输入性别:>");
scanf("%s", pc->data[pc->sz].sex);
printf("请输入地址:>");
scanf("%s", pc->data[pc->sz].addr);
printf("请输入电话:>");
scanf("%s", pc->data[pc->sz].tele);
printf("添加完成,请继续操作\n");
pc->sz++;
}
void delContact(Contact* pc) {
assert(pc);
printf("请选择删除的目标:>");
if (pc->sz == 0) {
return;
}
//删除的话只需要找到对应的要删除的数据，比如以名字为准，先找到，然后再讲其后面的元素覆盖前面的
int pos = searchContact(pc);
//换位置
if (pos == -1) {
printf("没有查找到该成员\n");
return;
}
for (int i = pos; i < pc->sz - 1; i++) {
pc->data[i] = pc->data[i + 1];
}
pc->sz--;//直接--不用管换位置之后最后一个数字的问题
printf("删除完成\n");
}
int searchContact(Contact* pc) {
assert(pc);
char name[20];
int pos = -1;
scanf("%s", name);
//查询
for (int i = 0; i < pc->sz; i++) {
if (strcmp(pc->data[i].name, name) == 0) {
pos = i;
}
}
return pos;
}
void showContact(Contact* pc) {
assert(pc);
if (pc->sz == 0) {
return;
}//可以有可无
printf("%-20s\t%-5s\t%-5s\t%-20s\t%-12s\n", "姓名", "年龄", "性别", "地址", "电话");
for (int i = 0; i < pc->sz; i++) {
printf("%-20s\t%-5d\t%-5s\t%-20s\t%-12s\n", pc->data[i].name, pc->data[i].age, pc->data[i].sex, pc->data[i].addr, pc->data[i].tele);
}
printf("打印完成\n");
}
void changeContact(Contact* pc) {
assert(pc);
//先找到
int pos = searchContact(pc);
printf("请输入名字:>");
scanf("%s", pc->data[pos].name);
printf("请输入年龄:>");
scanf("%d", &(pc->data[pos].age));
printf("请输入性别:>");
scanf("%s", pc->data[pos].sex);
printf("请输入地址:>");
scanf("%s", pc->data[pos].addr);
printf("请输入电话:>");
scanf("%s", pc->data[pos].tele);
printf("更改完成, 请继续操作\n");
}
void sortContact(Contact* pc) {
assert(pc);
if (pc->sz == 0) {
printf("通讯录中暂无元素\n");
return;
}
Contact s;
InitContact(&s);
for (int i = 0; i < pc->sz-1; i++) {
for (int j = 0; j < pc->sz-1-i; j++) {
if (strcmp(pc->data[j].name, pc->data[j + 1].name)==1) {
s.data[j] = pc->data[j];
pc->data[j] = pc->data[j + 1];
pc->data[j + 1] = s.data[j];
}
}
}
}
int compare(const void* e1, const void* e2) {
return *((int*)e1) - *((int*)e2);
}
void sort(Contact*pc) {
qsort(pc->data, pc->sz, sizeof(pc->data[0]), compare);
}3.Contact.h
#define _CRT_SECURE_NO_WARNINGS
//Contact 实现通讯录 头文件
#include<stdio.h>
#include<string.h>
#include<assert.h>
#include<malloc.h>
#include<stdlib.h>
#include<search.h>
#define MAX 100
#define NAME_MAX 20
#define SEX_MAX 5
#define ADDR_MAX 20
#define TELE_MAX 12
//下面两个define是用于动态通讯录的
#define MAX1 3 //表示第一次容积是多少
#define MAX2 2 //表示一次扩容多少
//构建通讯录所需的结构体
typedef struct PeopleInfo {
char name[NAME_MAX];//姓名
int age;//年龄
char sex[NAME_MAX];//性别
char addr[ADDR_MAX];//地址
char tele[TELE_MAX];//电话号码
}PeopleInfo;
//实现动态通讯录
typedef struct Contact {
PeopleInfo *data;//表示存储的通讯录最大人员数
int sz;//表示当前Contact通讯录人员个数
int capacity; //表示当前容量 作为扩容的依据
}Contact;
//初始化通讯录
void InitContact(Contact* pc);
//添加通讯录的信息
void addContact(Contact* pc);
//删除通讯录中的信息
void delContact(Contact* pc);
//查找通讯录成员信息
int searchContact(Contact* pc);
//打印
void showContact(Contact* pc);
//改变指定元素
void changeContact(Contact* pc);
//排序，按照名字排序
void sortContact(Contact* pc);Summarize
Both the static address book and the dynamic address book are relatively simple and easy to implement. The static address book stores members in the form of a fixed array. If the number of members is uncertain, it may waste space or may not be enough. However, the dynamic address book can better solve the problem of this space through continuous expansion, and will not cause too much waste.
Dynamic is to rely on functions such as malloc, free, calloc, and realloc to apply for space, maintain and expand capacity. In the next chapter, let’s explain the use and differences of these four functions in detail.