C-从不同的函数访问结构变量

#include <stdio.h>

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

void displayPerson(struct Person p) {
    printf("Name: %s\n", p.name);
    printf("Age: %d\n", p.age);
}

int main() {
    struct Person person1;
    strcpy(person1.name, "John");
    person1.age = 25;

    displayPerson(person1);

    return 0;
}

#include <stdio.h>

struct Point {
    int x;
    int y;
};

struct Point createPoint(int x, int y) {
    struct Point p;
    p.x = x;
    p.y = y;
    return p;
}

int main() {
    struct Point point1 = createPoint(3, 4);
    printf("Point: (%d, %d)\n", point1.x, point1.y);

    return 0;
}

#include <stdio.h>

struct Rectangle {
    int length;
    int width;
};

struct Rectangle rect;

void setDimensions(int length, int width) {
    rect.length = length;
    rect.width = width;
}

int calculateArea() {
    return rect.length * rect.width;
}

int main() {
    setDimensions(5, 3);
    printf("Area: %d\n", calculateArea());

    return 0;
}