v1/square.c


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#include <stdlib.h>
#include "square.h"

struct square
{
    struct shape *shape;
    double width;
};

/* Shape interface */

double shape_area_impl(struct shape *shape)
{
    struct square *square = (struct square *)shape;
    return square_area(square);
}

void shape_destroy_impl(struct shape *shape)
{
    struct square *square = (struct square *)shape;
    square_destroy(square);
}

struct shape *square_as_shape(struct square *square)
{
    return square->shape;
}

/* End of shape interface */

struct square *square_create(double width)
{
    struct square *square = malloc(sizeof(struct square));
    square->width = width;

    square->shape = shape_create(square, shape_area_impl, shape_destroy_impl);
    return square;
}

double square_area(struct square *square)
{
    return square->width * square->width;
}

void square_destroy(struct square *square)
{
    free(square);
}