《objective-c基础教程》学习笔记（三）—— 从结构体到面向对象

 1 /
 2 //  main.m
 3 //  ch3_OOP_Shapes
 4 //
 5 //  Created by pcbeta on 14-11-18.
 6 //  Copyright (c) 2014年 julian. All rights reserved.
 7 //  面向对象的基本实例，绘制几个几何图形
 8 
 9 #import <Foundation/Foundation.h>
10 /* 1. enum 枚举类型 */
11 //定义绘制图形的类型: 圆形，矩形，椭圆形
12 typedef enum{
13     kCircle,
14     kRectangle,
15     kEgg
16 } ShapeType;
17 
18 //定义绘制图形的颜色: 红色，绿色和蓝色
19 typedef enum{
20     kRedColor,
21     kGreenColor,
22     kBlueColor
23 } ShapeColor;
24 
25 /* 2. struct 结构体 */
26 //定义图形的基本属性
27 typedef struct{
28     int x, y, width, height;
29 } ShapeRect;
30 
31 //定义整体描述的形状
32 typedef struct{
33     ShapeType type;
34     ShapeColor color;
35     ShapeRect bounds;
36 } Shape;

 1     // 定义三个几何图形的数组
 2     Shape shapes[3];
 3     // 定义第一个几何图形为 红色的圆形，
 4     ShapeRect rect0 ={0,0,10,30};
 5     shapes[0].type = kCircle;
 6     shapes[0].fillColor = kRedColor;
 7     shapes[0].bounds = rect0;
 8     
 9     // 定义第一个几何图形为 绿色的矩形，
10     ShapeRect rect1 ={30,40,50,60};
11     shapes[1].type = kRectangle;
12     shapes[1].fillColor = kGreenColor;
13     shapes[1].bounds = rect1;
14     
15     // 定义第一个几何图形为 蓝色的椭圆形，
16     ShapeRect rect2 ={15,18,37,29};
17     shapes[2].type = kEgg;
18     shapes[2].fillColor = kBlueColor;
19     shapes[2].bounds = rect2;

 1 /* 3.定义获取颜色名称的函数 */
 2 NSString *colorName (ShapeColor fillColor)
 3 {
 4     switch(fillColor)
 5     {
 6         case kRedColor:
 7             return @"red";
 8             break;
 9         case kGreenColor:
10             return @"green";
11             break;
12         case kBlueColor:
13             return @"blue";
14             break;
15     }
16 }
17 
18 /* 4.定义几何画图方法 */
19 // 定义一个画圆的方法
20 void drawCircle(ShapeRect bounds, ShapeColor fillColor)
21 {
22     NSLog(@"Drawing a circle at (%d %d %d %d) in %@",
23           bounds.x,
24           bounds.y,
25           bounds.height,
26           bounds.width,
27           colorName(fillColor));
28 }
29 // 定义一个画矩形的方法
30 void drawRectangle(ShapeRect bounds, ShapeColor fillColor)
31 {
32     NSLog(@"Drawing a rectangle at (%d %d %d %d) in %@",
33           bounds.x,
34           bounds.y,
35           bounds.height,
36           bounds.width,
37           colorName(fillColor));
38 }
39 // 定义一个画椭圆的方法
40 void drawEgg(ShapeRect bounds, ShapeColor fillColor)
41 {
42     NSLog(@"Drawing a egg at (%d %d %d %d) in %@",
43           bounds.x,
44           bounds.y,
45           bounds.height,
46           bounds.width,
47           colorName(fillColor));
48 }

 1 //定义一个总的画图方法
 2 void drawShape(Shape shapes[], int count)
 3 {
 4     for(int i=0; i<count; i++)
 5     {
 6         switch(shapes[i].type){
 7             case kCircle:
 8                 drawCircle(shapes[i].bounds, shapes[i].fillColor);
 9                 break;
10             case kRectangle:
11                 drawRectangle(shapes[i].bounds, shapes[i].fillColor);
12                 break;
13             case kEgg:
14                 drawEgg(shapes[i].bounds, shapes[i].fillColor);
15                 break;
16         }
17     }
18 }

 1 int main(int argc, const char * argv[])
 2 {
 3     // 定义三个几何图形的数组
 4     Shape shapes[3];
 5     // 定义第一个几何图形为 红色的圆形，
 6     ShapeRect rect0 ={0,0,10,30};
 7     shapes[0].type = kCircle;
 8     shapes[0].fillColor = kRedColor;
 9     shapes[0].bounds = rect0;
10     
11     // 定义第二个几何图形为 绿色的矩形，
12     ShapeRect rect1 ={30,40,50,60};
13     shapes[1].type = kRectangle;
14     shapes[1].fillColor = kGreenColor;
15     shapes[1].bounds = rect1;
16     
17     // 定义第三个几何图形为 蓝色的椭圆形，
18     ShapeRect rect2 ={15,18,37,29};
19     shapes[2].type = kEgg;
20     shapes[2].fillColor = kBlueColor;
21     shapes[2].bounds = rect2;
22    
23     drawShape(shapes, 3);   
24     return 0;
25 }