C/C++ 结构体与指针笔记

2026-06-16 21:10:57 | 魂器工坊

结构体的定义与使用:

代码语言:javascript复制#include

#include

struct Student

{

int num;

char name[30];

char age;

};

int main(int argc, char* argv[])

{

struct Student stu = { 1001, "lyshark", 22 };

printf("普通引用: %d --> %s \n", stu.num, stu.name);

struct Student *ptr; // 定义结构指针

ptr = &stu; // 指针的赋值

printf("指针引用: %d --> %s \n", ptr->num, ptr->name);

system("pause");

return 0;

}动态分配结构体成员:

代码语言:javascript复制#include

#include

int main(int argc, char* argv[])

{

struct Student

{

int num;

char name[30];

char age;

};

struct Student *stu = malloc(sizeof(struct Student));

stu->num = 1001;

stu->age = 24;

strcpy(stu->name, "lyshark");

printf("姓名: %s 年龄: %d \n", stu->name, stu->age);

// ----------------------------------------------------------

struct Person

{

char *name;

int age;

}person;

struct Person *ptr = &person;

ptr->name = (char *)malloc(sizeof(char)* 20);

strcpy(ptr->name, "lyshark");

ptr->age = 23;

printf("姓名: %s 年龄: %d \n", ptr->name, ptr->age);

free(ptr->name);

system("pause");

return 0;

}结构体变量数组:

代码语言:javascript复制#include

#include

typedef struct Person

{

int uid;

char name[64];

}Person;

void Print(struct Person *p,int len)

{

for (int x = 0; x < len; x++)

{

printf("%d \n", p[x].uid);

}

}

int main(int argc, char* argv[])

{

// 栈上分配结构体(聚合初始化)

struct Person p1[] = {

{ 1, "aaa" },

{ 2, "bbb" },

{ 3, "ccc" },

};

int len = sizeof(p1) / sizeof(struct Person);

Print(p1, len);

// 在堆上分配

struct Person *p2 = malloc(sizeof(struct Person) * 5);

for (int x = 0; x < 5; x++)

{

p2[x].uid = x;

strcpy(p2[x].name, "aaa");

}

Print(p2, 5);

system("pause");

return 0;

}结构体深浅拷贝

代码语言:javascript复制#include

#include

typedef struct Person

{

int uid;

char *name;

}Person;

int main(int argc, char* argv[])

{

struct Person p1,p2;

p1.name = malloc(sizeof(char)* 64);

strcpy(p1.name, "admin");

p1.uid = 1;

p2.name = malloc(sizeof(char)* 64);

strcpy(p2.name, "guest");

p2.uid = 2;

// p2 = p1; 浅拷贝

// 深拷贝

if (p1.name != NULL)

{

free(p1.name);

p1.name == NULL;

}

p1.name = malloc(strlen(p2.name) + 1);

strcpy(p2.name, p1.name);

p2.uid = p1.uid;

printf("p2 -> %s \n", p2.name);

system("pause");

return 0;

}结构体字段排序: 首先对比结构中的UID,通过冒泡排序将UID从小到大排列,也可以通过Name字段进行排序.

代码语言:javascript复制#include

#include

struct Student

{

int uid;

char name[32];

double score;

};

int StructSort(struct Student *stu,int len)

{

for (int x = 0; x < len - 1; x++)

{

for (int y = 0; y < len - x - 1; y++)

{

// if (strcmp(stu[y].name, stu[y + 1].name) > 0)

if (stu[y].uid > stu[y + 1].uid)

{

// 结构体变量互换,将用户UID从小到大排列

struct Student tmp = stu[y];

stu[y] = stu[y + 1];

stu[y+1] = tmp;

}

}

}

return 0;

}

void MyPrint(struct Student *stu,int len)

{

for (int x = 0; x < len; x++)

printf("Uid: %d Name: %s Score: %.1f \n", stu[x].uid,stu[x].name,stu[x].score);

}

int main(int argc, char* argv[])

{

struct Student stu[3] = {

{8,"admin",79.5},

{5,"guest",89.5},

{1,"root",99},

};

StructSort(stu, 3); // 调用排序

MyPrint(stu, 3); // 输出结果

system("pause");

return 0;

}结构体数据之间的交换:

代码语言:javascript复制#include

#include

#include

struct Student

{

char *name;

int score[3];

};

int StructExchange(struct Student *stu, int len, char *str1,char *str2)

{

struct Student *ptr1;

struct Student *ptr2;

// 找到两个名字所对应的成绩

for (int x = 0; x < len; ++x)

{

if (!strcmp(stu[x].name, str1))

ptr1 = &stu[x];

if (!strcmp(stu[x].name, str2))

ptr2 = &stu[x];

}

// 开始交换两个人的成绩

for (int y = 0; y < 3; y++)

{

int tmp = ptr1->score[y];

ptr1->score[y] = ptr2->score[y];

ptr2->score[y] = tmp;

}

return 0;

}

void MyPrint(struct Student *stu,int len)

{

for (int x = 0; x < len; x++)

{

printf("Name: %s --> score: %d %d %d \n", stu[x].name, stu[x].score[0], stu[x].score[1], stu[x].score[2]);

}

}

int main(int argc, char* argv[])

{

struct Student stu[3];

// 动态开辟空间,并动态输入姓名与成绩

// admin 1 1 1 / guest 2 2 2 / root 3 3 3

for (int x = 0; x < 3; x++)

{

stu[x].name = (char *)malloc(sizeof(char) * 64); // 开辟空间

scanf("%s%d%d%d", stu[x].name, &stu[x].score[0], &stu[x].score[1], &stu[x].score[2]);

}

MyPrint(&stu, 3);

// 开始交换两个人名的成绩

StructExchange(&stu, 3, "root", "admin");

printf("----------------------------\n");

MyPrint(&stu, 3);

// 动态内存的释放

for (int y = 0; y < 3; y++)

free(stu[y].name);

system("pause");

return 0;

}结构体偏移量计算:

代码语言:javascript复制#include

#include

#include

int main(int argc, char* argv[])

{

struct Student

{

int uid;

char *name;

};

struct Student stu = { 1, "lyshark" };

int offset = (int *)( (char *)&stu + offsetof(struct Student, name) );

printf("指针首地址: %x \n", offset);

// =================================================================

// 第二种嵌套结构体取地址

struct SuperClass

{

int uid;

char *name;

struct stu

{

int sid;

char *s_name;

}stu;

};

struct SuperClass super = { 1001, "lyshark" ,1,"xiaowang"};

int offset1 = offsetof(struct SuperClass, stu);

int offset2 = offsetof(struct stu, sid);

// SuperClass + stu 找到 sid 首地址

int struct_offset = ((char *)&super + offset1) + offset2;

printf("sid首地址: %x --> %x \n", struct_offset, &super.stu.sid);

int stu_sid = *(int *) ((char *)&super + offset1) + offset2;

printf("sid里面的数值是: %d \n", stu_sid);

int stu_sid_struct = ((struct stu *)((char *)&super + offset1))->sid;

printf("sid里面的数值是: %d \n", stu_sid_struct);

system("pause");

return 0;

}结构体嵌套一级指针

代码语言:javascript复制#include

#include

typedef struct Person

{

int id;

char *name;

int age;

}Person;

// 分配内存空间,每一个二级指针中存放一个一级指针

struct Person ** allocateSpace()

{

// 分配3个一级指针,每一个指针指向一个结构首地址

struct Person **tmp = malloc(sizeof(struct Person *) * 3);

for (int x = 0; x < 3; x++)

{

tmp[x] = malloc(sizeof(struct Person)); // (真正的)分配一个存储空间

tmp[x]->name = malloc(sizeof(char) * 64); // 分配存储name的空间

sprintf(tmp[x]->name, "name_%d", x);

tmp[x]->id = x;

tmp[x]->age = x + 10;

}

return tmp;

}

// 循环输出数据

void MyPrint(struct Person **person)

{

for (int x = 0; x < 3; x++)

{

printf("Name: %s \n", person[x]->name);

}

}

// 释放内存空间,从后向前,从小到大释放

void freeSpace(struct Person **person)

{

if (person != NULL)

{

for (int x = 0; x < 3; x++)

{

if (person[x]->name != NULL)

{

printf("%s 内存被释放 \n",person[x]->name);

free(person[x]->name);

person[x]->name = NULL;

}

free(person[x]);

person[x] = NULL;

}

free(person);

person = NULL;

}

}

int main(int argc, char* argv[])

{

struct Person **person = NULL;

person = allocateSpace();

MyPrint(person);

freeSpace(person);

system("pause");

return 0;

}结构体嵌套二级指针

代码语言:javascript复制#include

#include

struct Student

{

char * name;

}Student;

struct Teacher

{

char *name;

char **student;

}Teacher;

void allocateSpace(struct Teacher ***ptr)

{

// 首先分配三个二级指针,分别指向三个老师的结构首地址

struct Teacher **teacher_ptr = malloc(sizeof(struct Teacher *) * 3);

for (int x = 0; x < 3; x++)

{

// 先来分配老师姓名存储字符串,然后赋初值

teacher_ptr[x] = malloc(sizeof(struct Teacher)); // 给teacher_ptr整体分配空间

teacher_ptr[x]->name = malloc(sizeof(char)* 64); // 给teacher_ptr里面的name分配空间

sprintf(teacher_ptr[x]->name, "teacher_%d", x); // 分配好空间之后,将数据拷贝到name里面

// -------------------------------------------------------------------------------------

// 接着分配该老师管理的学生数据,默认管理四个学生

teacher_ptr[x]->student = malloc(sizeof(char *) * 4); // 给teacher_ptr 里面的student分配空间

for (int y = 0; y < 4; y++)

{

teacher_ptr[x]->student[y] = malloc(sizeof(char) * 64);

sprintf(teacher_ptr[x]->student[y], "%s_stu_%d", teacher_ptr[x]->name, y);

}

}

// 最后将结果抛出去

*ptr = teacher_ptr;

}

// 输出老师和学生数据

void MyPrint(struct Teacher **ptr)

{

for (int x = 0; x < 3; x++)

{

printf("老师姓名: %s \n", ptr[x]->name);

for (int y = 0; y < 4; y++)

{

printf("--> 学生: %s \n", ptr[x]->student[y]);

}

}

}

// 最后释放内存

void freeSpace(struct Teacher **ptr)

{

for (int x = 0; x < 3; x++)

{

if (ptr[x]->name != NULL)

{

free(ptr[x]->name);

ptr[x]->name = NULL;

}

for (int y = 0; y < 4; y++)

{

if (ptr[x]->student[y] != NULL)

{

free(ptr[x]->student[y]);

ptr[x]->student[y] = NULL;

}

}

free(ptr[x]->student);

ptr[x]->student = NULL;

}

}

int main(int argc, char* argv[])

{

struct Teacher **teacher_ptr = NULL;

allocateSpace(&teacher_ptr);

MyPrint(teacher_ptr);

freeSpace(teacher_ptr);

system("pause");

return 0;

}结构体内嵌共用体:

代码语言:javascript复制#define _CRT_SECURE_NO_WARNINGS

#include

#include

struct Person

{

int uid; // 编号

char name[20]; // 姓名

char jobs; // 老师=t 或 学生 = s

union

{

char stu_class[32]; // 学生所在班级

char tea_class[32]; // 老师的所教课程

}category;

};

int main(int argc, char* argv[])

{

struct Person person[3];

for (int x = 0; x < 3; x++)

{

// 首先输入前三项,因为这三个数据是通用的,老师学生都存在的属性

printf("输入: ID 姓名 工作类型(s/t) \n");

scanf("%d %s %c", &person[x].uid, &person[x].name, &person[x].jobs);

if (person[x].jobs == 's') // 如果是学生,输入stu_class

scanf("%s", person[x].category.stu_class);

if (person[x].jobs == 't') // 如果是老师,输入tea_class

scanf("%s", person[x].category.tea_class);

}

printf("--------------------------------------------------------------\n");

for (int y = 0; y < 3; y++)

{

if (person[y].jobs == 's')

printf("老师: %s 职务: %s \n", person[y].name, person[y].category.tea_class);

if (person[y].jobs == 't')

printf("学生: %s 班级: %s \n", person[y].name, person[y].category.stu_class);

}

system("pause");

return 0;

}结构体与链表结构体基本定义:

代码语言:javascript复制#include

typedef struct Person

{

int uid;

char name[64];

}Person;

int main(int argc, char* argv[])

{

// 在栈上分配空间

struct Person s1 = { 100, "admin" };

printf("%s \n", s1.name);

// 在堆上分配空间

struct Person *s2 = malloc(sizeof(struct Person));

strcpy(s2->name, "lyshark");

printf("%s \n", s2->name);

system("pause");

return 0;

}结构体变量数组:

代码语言:javascript复制#include

#include

typedef struct Person

{

int uid;

char name[64];

}Person;

void Print(struct Person *p,int len)

{

for (int x = 0; x < len; x++)

{

printf("%d \n", p[x].uid);

}

}

int main(int argc, char* argv[])

{

// 栈上分配结构体(聚合初始化)

struct Person p1[] = {

{ 1, "aaa" },

{ 2, "bbb" },

{ 3, "ccc" },

};

int len = sizeof(p1) / sizeof(struct Person);

Print(p1, len);

// 在堆上分配

struct Person *p2 = malloc(sizeof(struct Person) * 5);

for (int x = 0; x < 5; x++)

{

p2[x].uid = x;

strcpy(p2[x].name, "aaa");

}

Print(p2, 5);

system("pause");

return 0;

}结构体深浅拷贝

代码语言:javascript复制#include

#include

typedef struct Person

{

int uid;

char *name;

}Person;

int main(int argc, char* argv[])

{

struct Person p1,p2;

p1.name = malloc(sizeof(char)* 64);

strcpy(p1.name, "admin");

p1.uid = 1;

p2.name = malloc(sizeof(char)* 64);

strcpy(p2.name, "guest");

p2.uid = 2;

// p2 = p1; 浅拷贝

// 深拷贝

if (p1.name != NULL)

{

free(p1.name);

p1.name == NULL;

}

p1.name = malloc(strlen(p2.name) + 1);

strcpy(p2.name, p1.name);

p2.uid = p1.uid;

printf("p2 -> %s \n", p2.name);

system("pause");

return 0;

}结构体嵌套一级指针

代码语言:javascript复制#include

#include

typedef struct Person

{

int id;

char *name;

int age;

}Person;

// 分配内存空间,每一个二级指针中存放一个一级指针

struct Person ** allocateSpace()

{

// 分配3个一级指针,每一个指针指向一个结构首地址

struct Person **tmp = malloc(sizeof(struct Person *) * 3);

for (int x = 0; x < 3; x++)

{

tmp[x] = malloc(sizeof(struct Person)); // (真正的)分配一个存储空间

tmp[x]->name = malloc(sizeof(char) * 64); // 分配存储name的空间

sprintf(tmp[x]->name, "name_%d", x);

tmp[x]->id = x;

tmp[x]->age = x + 10;

}

return tmp;

}

// 循环输出数据

void MyPrint(struct Person **person)

{

for (int x = 0; x < 3; x++)

{

printf("Name: %s \n", person[x]->name);

}

}

// 释放内存空间,从后向前,从小到大释放

void freeSpace(struct Person **person)

{

if (person != NULL)

{

for (int x = 0; x < 3; x++)

{

if (person[x]->name != NULL)

{

printf("%s 内存被释放 \n",person[x]->name);

free(person[x]->name);

person[x]->name = NULL;

}

free(person[x]);

person[x] = NULL;

}

free(person);

person = NULL;

}

}

int main(int argc, char* argv[])

{

struct Person **person = NULL;

person = allocateSpace();

MyPrint(person);

freeSpace(person);

system("pause");

return 0;

}结构体嵌套二级指针

代码语言:javascript复制#include

#include

struct Student

{

char * name;

}Student;

struct Teacher

{

char *name;

char **student;

}Teacher;

void allocateSpace(struct Teacher ***ptr)

{

// 首先分配三个二级指针,分别指向三个老师的结构首地址

struct Teacher **teacher_ptr = malloc(sizeof(struct Teacher *) * 3);

for (int x = 0; x < 3; x++)

{

// 先来分配老师姓名存储字符串,然后赋初值

teacher_ptr[x] = malloc(sizeof(struct Teacher)); // 给teacher_ptr整体分配空间

teacher_ptr[x]->name = malloc(sizeof(char)* 64); // 给teacher_ptr里面的name分配空间

sprintf(teacher_ptr[x]->name, "teacher_%d", x); // 分配好空间之后,将数据拷贝到name里面

// -------------------------------------------------------------------------------------

// 接着分配该老师管理的学生数据,默认管理四个学生

teacher_ptr[x]->student = malloc(sizeof(char *) * 4); // 给teacher_ptr 里面的student分配空间

for (int y = 0; y < 4; y++)

{

teacher_ptr[x]->student[y] = malloc(sizeof(char) * 64);

sprintf(teacher_ptr[x]->student[y], "%s_stu_%d", teacher_ptr[x]->name, y);

}

}

// 最后将结果抛出去

*ptr = teacher_ptr;

}

// 输出老师和学生数据

void MyPrint(struct Teacher **ptr)

{

for (int x = 0; x < 3; x++)

{

printf("老师姓名: %s \n", ptr[x]->name);

for (int y = 0; y < 4; y++)

{

printf("--> 学生: %s \n", ptr[x]->student[y]);

}

}

}

// 最后释放内存

void freeSpace(struct Teacher **ptr)

{

for (int x = 0; x < 3; x++)

{

if (ptr[x]->name != NULL)

{

free(ptr[x]->name);

ptr[x]->name = NULL;

}

for (int y = 0; y < 4; y++)

{

if (ptr[x]->student[y] != NULL)

{

free(ptr[x]->student[y]);

ptr[x]->student[y] = NULL;

}

}

free(ptr[x]->student);

ptr[x]->student = NULL;

}

}

int main(int argc, char* argv[])

{

struct Teacher **teacher_ptr = NULL;

allocateSpace(&teacher_ptr);

MyPrint(teacher_ptr);

freeSpace(teacher_ptr);

system("pause");

return 0;

}静态链表 理解一下

代码语言:javascript复制#include

#include

// 定义链表节点类型

struct LinkNode

{

int data;

struct LinkNode *next;

};

int main(int argc, char* argv[])

{

struct LinkNode node1 = { 10, NULL };

struct LinkNode node2 = { 20, NULL };

struct LinkNode node3 = { 30, NULL };

struct LinkNode node4 = { 40, NULL };

node1.next = &node2;

node2.next = &node3;

node3.next = &node4;

node4.next = NULL;

// 遍历链表结构

struct LinkNode *ptr = &node1;

while (ptr != NULL)

{

printf("%d \n", ptr->data);

ptr = ptr->next;

}

system("pause");

return 0;

}动态链表

代码语言:javascript复制#include

#include

// 定义链表节点类型

struct LinkNode

{

int data;

struct LinkNode *next;

};

struct LinkNode *init_link()

{ // 创建一个头结点,头结点不需要添加任何数据

struct LinkNode *header = malloc(sizeof(struct LinkNode));

header->data = 0;

header->next = NULL;

struct LinkNode *p_end = header; // 创建一个尾指针

int val = -1;

while (1)

{

scanf("%d", &val); // 输入插入的数据

if (val == -1) // 如果输入-1说明输入结束了

break;

// 先创建新节点

struct LinkNode *newnode = malloc(sizeof(struct LinkNode));

newnode->data = val;

newnode->next = NULL;

// 将节点插入到链表中

p_end->next = newnode;

// 更新尾部指针指向

p_end = newnode;

}

return header;

}

// 遍历链表

int foreach_link(struct LinkNode *header)

{

if (NULL == header || header->next == NULL)

return 0;

while (header->next != NULL)

{

printf("%d \n", header->data);

header = header->next;

}

return 1;

}

// 在header节点中oldval插入数据

void insert_link(struct LinkNode *header,int oldval,int newval)

{

struct LinkNode *pPrev = header;

struct LinkNode *Current = pPrev->next;

if (NULL == header)

return;

while (Current != NULL)

{

if (Current->data == oldval)

break;

pPrev = Current;

Current = Current->next;

}

// 如果值不存在则默认插入到尾部

//if (Current == NULL)

// return;

// 创建新节点

struct LinkNode *newnode = malloc(sizeof(struct LinkNode));

newnode->data = newval;

newnode->next = NULL;

// 新节点插入到链表中

newnode->next = Current;

pPrev->next = newnode;

}

// 清空链表

void clear_link(struct LinkNode *header)

{

// 辅助指针

struct LinkNode *Current = header->next;

while (Current != NULL)

{

// 保存下一个节点地址

struct LinkNode *pNext = Current->next;

printf("清空数据: %d \n", Current->data);

free(Current);

Current = pNext;

}

header->next = NULL;

}

// 删除值为val的节点

int remove_link(struct LinkNode *header, int delValue)

{

if (NULL == header)

return;

// 设置两个指针,指向头结点和尾结点

struct LinkNode *pPrev = header;

struct LinkNode *Current = pPrev->next;

while (Current != NULL)

{

if (Current->data == delValue)

{

// 删除节点的过程

pPrev->next = Current->next;

free(Current);

Current = NULL;

}

}

// 移动两个辅助指针

pPrev = Current;

Current = Current->next;

}

// 销毁链表

void destroy_link(struct LinkNode *header)

{

if (NULL == header)

return;

struct LinkNode *Curent = header;

while (Curent != NULL)

{

// 先来保存一下下一个节点地址

struct LinkNode *pNext = Curent->next;

free(Curent);

// 指针向后移动

Curent = pNext;

}

}

// 反响排序

void reverse_link(struct LinkNode *header)

{

if (NULL == header)

return;

struct LinkNode *pPrev = NULL;

struct LinkNode *Current = header->next;

struct LinkNode * pNext = NULL;

while (Current != NULL)

{

pNext = Current->next;

Current->next = pPrev;

pPrev = Current;

Current = pNext;

}

header->next = pPrev;

}

int main(int argc, char* argv[])

{

struct LinkNode * header = init_link();

reverse_link(header);

foreach_link(header);

clear_link(header);

system("pause");

return 0;

}