题解 | KiKi设计类继承

#include <stdio.h>

// write your code here......

typedef struct shape {
    int x;
    int y;
} shape_t;

typedef struct Rectangle rectangle_t;
typedef struct Rectangle {
    int width;
    int height;
    shape_t point;
    int (*get_area)(rectangle_t* obj);
} rectangle_t;

int GetRecArea(rectangle_t* obj) {
    return obj->width * obj->height;
}

typedef struct Circle circle_t;
typedef struct Circle {
    int radius;
    shape_t point;
    double (*get_area)(circle_t* obj);
} circle_t;

double GetCircleArea(circle_t* obj) {
    return 3.14 * obj->radius * obj->radius;
}

typedef struct Square square_t;
typedef struct Square {
    rectangle_t rec;
    int (*get_area)(square_t* obj);
} square_t;

int GetSquareArea(square_t* obj) {
    return obj->rec.width * obj->rec.width;
}

int main() {

    int length, width, radius, side_length;
    scanf("%d%d", &length, &width);
    scanf("%d", &radius);
    scanf("%d", &side_length);

    // write your code here......
    rectangle_t rec = {
        .width = width,
        .height = length,
        .get_area = GetRecArea
    };

    printf("%d\n", rec.get_area(&rec));

    circle_t cir = {
        .radius = radius,
        .get_area = GetCircleArea
    };

    printf("%g\n", cir.get_area(&cir));

    square_t sq = {
        .rec = {
            .width = side_length,
            .height = side_length,
            .get_area = GetRecArea
        },
        .get_area = GetSquareArea
    };

    printf("%d\n", sq.get_area(&sq));

    return 0;
}