介绍

在C语言中，结构体指针是一种非常有用的工具，它允许我们通过指针来操作结构体，尤其是在处理动态内存分配或函数参数传递时。以下是关于C语言结构体指针的详细讲解。

定义结构体指针

首先，我们需要定义一个结构体。例如，定义一个表示学生信息的结构体：

#include <stdio.h>struct Student {char name[50];int age;float gpa;
};

然后，我们可以定义一个指向该结构体的指针：

struct Student *studentPtr;

初始化结构体指针

指向现有结构体变量

我们可以让结构体指针指向一个已有的结构体变量：

struct Student student1 = {"Alice", 20, 3.5};
struct Student *studentPtr = &student1;

动态分配内存

我们也可以使用动态内存分配来初始化结构体指针：

struct Student *studentPtr = (struct Student *)malloc(sizeof(struct Student));
if (studentPtr == NULL) {printf("Memory allocation failed\n");return 1;
}

访问结构体成员

使用结构体指针访问成员

当我们有一个结构体指针时，可以使用箭头操作符 -> 来访问结构体成员：

studentPtr->age = 21;
printf("Name: %s, Age: %d, GPA: %.2f\n", studentPtr->name, studentPtr->age, studentPtr->gpa);

通过指针和解引用

我们也可以使用指针和解引用操作符 * 组合来访问结构体成员：

(*studentPtr).age = 22;
printf("Name: %s, Age: %d, GPA: %.2f\n", (*studentPtr).name, (*studentPtr).age, (*studentPtr).gpa);

不过，使用箭头操作符 -> 更加简洁和常见。

结构体指针作为函数参数

将结构体指针作为函数参数，可以高效地传递结构体数据，避免大结构体的拷贝。以下是一个示例：

void printStudent(struct Student *student) {printf("Name: %s, Age: %d, GPA: %.2f\n", student->name, student->age, student->gpa);
}int main() {struct Student student1 = {"Alice", 20, 3.5};printStudent(&student1);struct Student *studentPtr = (struct Student *)malloc(sizeof(struct Student));if (studentPtr == NULL) {printf("Memory allocation failed\n");return 1;}strcpy(studentPtr->name, "Bob");studentPtr->age = 21;studentPtr->gpa = 3.7;printStudent(studentPtr);free(studentPtr);return 0;
}

使用结构体指针构建链表

结构体指针在构建复杂数据结构（如链表）时非常有用。以下是一个简单的单链表示例：

#include <stdio.h>
#include <stdlib.h>// 定义链表节点
struct Node {int data;struct Node *next;
};// 创建新节点
struct Node* createNode(int data) {struct Node *newNode = (struct Node *)malloc(sizeof(struct Node));if (newNode == NULL) {printf("Memory allocation failed\n");exit(1);}newNode->data = data;newNode->next = NULL;return newNode;
}// 打印链表
void printList(struct Node *head) {struct Node *current = head;while (current != NULL) {printf("%d -> ", current->data);current = current->next;}printf("NULL\n");
}int main() {struct Node *head = createNode(1);head->next = createNode(2);head->next->next = createNode(3);printList(head);// 释放内存struct Node *current = head;struct Node *next;while (current != NULL) {next = current->next;free(current);current = next;}return 0;
}

高级用法

当然，这里有更多关于C语言结构体指针的高级用法和注意事项。

多级指针（指向指针的指针）

有时候，我们可能需要使用指向指针的指针，尤其是在处理动态二维数组或在函数中修改指针变量时。以下是一个简单的示例：

#include <stdio.h>
#include <stdlib.h>struct Student {char name[50];int age;float gpa;
};void allocateStudent(struct Student **studentPtr) {*studentPtr = (struct Student *)malloc(sizeof(struct Student));if (*studentPtr == NULL) {printf("Memory allocation failed\n");exit(1);}
}int main() {struct Student *studentPtr = NULL;allocateStudent(&studentPtr);strcpy(studentPtr->name, "Alice");studentPtr->age = 20;studentPtr->gpa = 3.5;printf("Name: %s, Age: %d, GPA: %.2f\n", studentPtr->name, studentPtr->age, studentPtr->gpa);free(studentPtr);return 0;
}

在这个例子中，allocateStudent 函数使用了双重指针（struct Student **）来分配内存并修改指针变量。

动态二维数组

使用结构体指针可以创建动态二维数组。例如，一个表示学生成绩的二维数组：

#include <stdio.h>
#include <stdlib.h>struct Grade {int studentId;float score;
};int main() {int rows = 3;int cols = 2;// 分配行指针数组struct Grade **grades = (struct Grade **)malloc(rows * sizeof(struct Grade *));if (grades == NULL) {printf("Memory allocation failed\n");return 1;}// 分配每行的列for (int i = 0; i < rows; i++) {grades[i] = (struct Grade *)malloc(cols * sizeof(struct Grade));if (grades[i] == NULL) {printf("Memory allocation failed\n");return 1;}}// 初始化数据for (int i = 0; i < rows; i++) {for (int j = 0; j < cols; j++) {grades[i][j].studentId = i * cols + j;grades[i][j].score = (i + 1) * (j + 1) * 10.0;}}// 输出数据for (int i = 0; i < rows; i++) {for (int j = 0; j < cols; j++) {printf("Student ID: %d, Score: %.2f\n", grades[i][j].studentId, grades[i][j].score);}}// 释放内存for (int i = 0; i < rows; i++) {free(grades[i]);}free(grades);return 0;
}

结构体指针与链表操作

链表是一种常见的数据结构，使用结构体指针实现链表操作是一个非常好的练习。以下是一些基本的链表操作示例，包括插入和删除节点：

插入节点

void insertAtBeginning(struct Node **head, int data) {struct Node *newNode = createNode(data);newNode->next = *head;*head = newNode;
}void insertAtEnd(struct Node **head, int data) {struct Node *newNode = createNode(data);if (*head == NULL) {*head = newNode;return;}struct Node *current = *head;while (current->next != NULL) {current = current->next;}current->next = newNode;
}

删除节点

void deleteNode(struct Node **head, int key) {struct Node *temp = *head, *prev = NULL;// 如果头节点持有要删除的值if (temp != NULL && temp->data == key) {*head = temp->next;free(temp);return;}// 搜索要删除的节点while (temp != NULL && temp->data != key) {prev = temp;temp = temp->next;}// 如果没有找到该值if (temp == NULL) return;// 解除链接并释放内存prev->next = temp->next;free(temp);
}

高级链表操作

链表反转

反转链表是一个常见的操作，以下是反转单链表的代码示例：

#include <stdio.h>
#include <stdlib.h>struct Node {int data;struct Node *next;
};struct Node* createNode(int data) {struct Node *newNode = (struct Node *)malloc(sizeof(struct Node));if (newNode == NULL) {printf("Memory allocation failed\n");exit(1);}newNode->data = data;newNode->next = NULL;return newNode;
}void reverseList(struct Node **head) {struct Node *prev = NULL;struct Node *current = *head;struct Node *next = NULL;while (current != NULL) {next = current->next;current->next = prev;prev = current;current = next;}*head = prev;
}void printList(struct Node *head) {struct Node *current = head;while (current != NULL) {printf("%d -> ", current->data);current = current->next;}printf("NULL\n");
}int main() {struct Node *head = createNode(1);head->next = createNode(2);head->next->next = createNode(3);printf("Original List:\n");printList(head);reverseList(&head);printf("Reversed List:\n");printList(head);// 释放内存struct Node *current = head;struct Node *next;while (current != NULL) {next = current->next;free(current);current = next;}return 0;
}

链表合并

合并两个有序链表是一个常见操作，以下是合并两个有序链表的代码示例：

struct Node* mergeLists(struct Node *l1, struct Node *l2) {if (l1 == NULL) return l2;if (l2 == NULL) return l1;struct Node *head = NULL;if (l1->data < l2->data) {head = l1;l1 = l1->next;} else {head = l2;l2 = l2->next;}struct Node *current = head;while (l1 != NULL && l2 != NULL) {if (l1->data < l2->data) {current->next = l1;l1 = l1->next;} else {current->next = l2;l2 = l2->next;}current = current->next;}if (l1 != NULL) {current->next = l1;} else {current->next = l2;}return head;
}

深拷贝结构体

有时候我们需要对结构体进行深拷贝，即复制结构体及其所有嵌套的内容。以下是一个深拷贝简单结构体的示例：

#include <stdio.h>
#include <string.h>
#include <stdlib.h>struct Address {char street[100];char city[50];char state[50];int zip;
};struct Student {char name[50];int age;float gpa;struct Address *address;
};struct Student* deepCopyStudent(const struct Student *original) {struct Student *copy = (struct Student *)malloc(sizeof(struct Student));if (copy == NULL) {printf("Memory allocation failed\n");exit(1);}strcpy(copy->name, original->name);copy->age = original->age;copy->gpa = original->gpa;copy->address = (struct Address *)malloc(sizeof(struct Address));if (copy->address == NULL) {printf("Memory allocation failed\n");free(copy);exit(1);}memcpy(copy->address, original->address, sizeof(struct Address));return copy;
}int main() {struct Address address = {"123 Maple St", "Springfield", "IL", 62701};struct Student student1 = {"Alice", 20, 3.5, &address};struct Student *studentCopy = deepCopyStudent(&student1);// 修改原始数据以验证深拷贝strcpy(student1.address->city, "Changed City");printf("Original Student: %s, %s\n", student1