结构指针指定的地址

#include <stdio.h>
#include <stdlib.h>

// 定义一个结构体
struct Student {
    char name[50];
    int age;
    float score;
};

int main() {
    // 创建一个结构体变量
    struct Student student1 = {"Alice", 20, 95.5};

    // 创建一个指向结构体的指针
    struct Student *ptr = &student1;

    // 通过指针访问结构体成员
    printf("Name: %s\n", ptr->name);
    printf("Age: %d\n", ptr->age);
    printf("Score: %.2f\n", ptr->score);

    // 动态分配内存并使用结构指针
    struct Student *ptr2 = (struct Student *)malloc(sizeof(struct Student));
    if (ptr2 != NULL) {
        strcpy(ptr2->name, "Bob");
        ptr2->age = 22;
        ptr2->score = 88.0;

        printf("Name: %s\n", ptr2->name);
        printf("Age: %d\n", ptr2->age);
        printf("Score: %.2f\n", ptr2->score);

        // 释放内存
        free(ptr2);
    }

    return 0;
}

// 错误示例
struct Student *ptr = NULL;
printf("%s", ptr->name); // 这将导致段错误

// 正确示例
struct Student *ptr = (struct Student *)malloc(sizeof(struct Student));
if (ptr != NULL) {
    strcpy(ptr->name, "Alice");
    printf("%s", ptr->name);
    free(ptr); // 释放内存
}