C语言实现的OOP
我倒不是为了OOP而OOP,实在是OOP的一些特征,例如封装,多态其实是软件工程思想,这些思想不分语言,遵循了这些思想可以使得程序更有弹性,更易修改和维护,避免僵化,脆弱
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shape.h 该文件定义的是图形接口,所有具体图形都必须实现自己计算面积,周长等API
#ifndef SHAPE_H
#define SHAPE_H
typedef struct shape_t
{
void *shapeData;
void (*area)(void *);
void (*release)(void *);
}Shape;
#endifcircle.h 圆形接口
#ifndef CIRCLE_H
#define CIRCLE_H
typedef struct
{
double r;
}CircleData;
typedef struct
{
void *shapeData;
void (*area)(void *);
void (*release)(void *);
}Circle;
Circle *makeCircle(double r);
#endifcircle.c 圆形的实现代码,static修饰的函数其实相当于private函数
#include <assert.h>
#include <stdlib.h>
#include <stdio.h>
#include "circle.h"
const double PI = 3.14159;
static void area(void *shape)
{
Circle *_circle = (Circle *)shape;
CircleData* data = (CircleData*)_circle->shapeData;
printf("the circle area is %f \n", data->r * data->r * PI);
}
static void release(void *shape)
{
Circle *_circle = (Circle *)shape;
CircleData* data = (CircleData*)_circle->shapeData;
free(data);
free(_circle);
}
Circle *makeCircle(double r)
{
CircleData* circleData = (CircleData*)malloc(sizeof(CircleData));
Circle* circle = (Circle*)malloc(sizeof(Circle));
assert(circleData != NULL);
assert(circle != NULL);
assert(r > 0);
circleData->r = r;
circle->shapeData = circleData;
circle->area = &area;
circle->release = &release;
return circle;
}square.h
#ifndef SQUARE_H
#define SQUARE_H
typedef struct
{
double x;
double y;
}SquareData;
typedef struct
{
void *shapeData;
void (*area)(void *);
void (*release)(void *);
}Square;
Square *makeSquare(double x, double y);
#endifsquare.c
#include <assert.h>
#include <stdlib.h>
#include <stdio.h>
#include "square.h"
static void area(void *shape)
{
Square *square = (Square *)shape;
SquareData* data = (SquareData*)square->shapeData;
printf("the square area is %f \n", data->x * data->y);
}
static void release(void *shape)
{
Square *square = (Square *)shape;
SquareData* data = (SquareData*)square->shapeData;
free(data);
free(square);
}
Square *makeSquare(double x, double y)
{
SquareData* squareData = (SquareData*)malloc(sizeof(SquareData));
Square* square = (Square*)malloc(sizeof(Square));
assert(squareData != NULL);
assert(square != NULL);
assert(x > 0 && y > 0);
squareData->x = x;
squareData->y = y;
square->shapeData = squareData;
square->area = &area;
square->release = &release;
return square;
}main.c 所有的工作,都为了它,是为了让它的代码稳定
#include <stdio.h>
#include "shape.h"
#include "circle.h"
#include "square.h"
void printShapeArea(Shape **shape,int length)
{
int i=0;
for(i=0;i<length;i++)
{
shape[i]->area(shape[i]);
shape[i]->release(shape[i]);
}
}
int main()
{
Shape *p[3] = {(Shape*)makeCircle(3.2),(Shape*)makeCircle(3.2),(Shape*)makeSquare(3.1,4)};
printShapeArea(p,3);
return 0;
}
总结:
printShapeArea 函数并不知道传入的图形列表分别都是哪些图形,这些图形又都怎么计算面积和周长,它唯一知道的是,这些图形计算面积和周长的接口是什么,通过这个接口计算就好了
补充:软件开发 , C语言 ,