尝试访问函数外部的结构变量后出现分段故障

#include <stdio.h>

struct Person {
    char name[20];
    int age;
};

void modifyPerson(struct Person* person) {
    strcpy(person->name, "John");
    person->age = 25;
}

int main() {
    struct Person p;
    modifyPerson(&p);
    printf("Name: %s, Age: %d\n", p.name, p.age);
    return 0;
}

#include <stdio.h>

struct Person {
    char name[20];
    int age;
};

struct Person p;

void modifyPerson() {
    strcpy(p.name, "John");
    p.age = 25;
}

int main() {
    modifyPerson();
    printf("Name: %s, Age: %d\n", p.name, p.age);
    return 0;
}

#include <stdio.h>

struct Person {
    char name[20];
    int age;
};

void modifyPerson(struct Person* person) {
    strcpy(person->name, "John");
    person->age = 25;
}

int main() {
    struct Person p;
    struct Person* ptr = &p;
    modifyPerson(ptr);
    printf("Name: %s, Age: %d\n", p.name, p.age);
    return 0;
}