1 // 2 // main.m 3 // TEXT2 car 4 // 5 // Created by ponytai1 on 16/11/4. 6 // Copyright © 2016年 ponytai1. All rights reserved. 7 // 8 9 #import<Foundation/Foundation.h> 10 @interface Tire:NSObject 11 { 12 13 } 14 @end //tire interface 15 16 17 @implementation Tire 18 -(NSString *)description 19 { 20 return (@"i am a tire"); 21 } 22 @end //tire implementation 23 24 25 @interface Engine:NSObject 26 { 27 28 } 29 @end //endine interface 30 31 32 @implementation Engine 33 -(NSString*)description 34 { 35 return (@"i am a engine"); 36 } 37 @end //engine implementation 38 39 40 @interface V8engine:Engine 41 @end //v8engine interface 42 43 44 @implementation V8engine 45 -(NSString *) description 46 { 47 return(@"i am a better engine"); 48 } 49 @end //v8engine implementation 50 51 52 @interface BetterTire:Tire 53 @end //BetterTire interface 54 55 56 @implementation BetterTire 57 -(NSString *) description 58 { 59 return(@"i am a better tire"); 60 } 61 @end //BetterTire interface 62 63 64 @interface Car:NSObject 65 { 66 Tire *tires[4]; 67 Engine *engine; 68 } 69 -(void)print; 70 -(void)setTire:(Tire *)tire atIndex:(int) index; 71 -(Tire *)tireAtIndex:(int)index; 72 -(void)setEngine:(Engine *)newEngine; 73 -(Engine *)engine; 74 75 @end //car interface 76 77 78 @implementation Car 79 -(id)init 80 { 81 if(self = [super init]) 82 { 83 engine = [Engine new]; 84 tires[0] = [Tire new]; 85 tires[1] = [Tire new]; 86 tires[2] = [Tire new]; 87 tires[3] = [Tire new]; 88 } 89 return self; 90 } 91 -(void)setTire:(Tire *)tire atIndex:(int)index 92 { 93 if(index > 3 ||index < 0) 94 { 95 NSLog(@"index is error"); 96 exit(1); 97 } 98 tires[index] = tire; 99 } 100 -(void)setEngine:(Engine *)newEngine 101 { 102 engine = newEngine; 103 } 104 -(Tire *)tireAtIndex:(int)index 105 { 106 if(index > 3|| index < 0) 107 { 108 NSLog(@"index is error"); 109 exit(1); 110 } 111 return tires[index]; 112 } 113 -(Engine *)engine 114 { 115 return engine; 116 } 117 -(void)print 118 { 119 NSLog(@"%@",engine); 120 NSLog(@"%@",tires[0]); 121 NSLog(@"%@",tires[1]); 122 NSLog(@"%@",tires[2]); 123 NSLog(@"%@",tires[3]); 124 } 125 @end //car implementation 126 127 128 int main(int argc,const char* argv[]) 129 { 130 Car *car; 131 car = [Car new]; 132 Engine *engine = [Engine new]; 133 [car setEngine:(Engine *)engine]; 134 for(int i = 0;i < 4;i++) 135 { 136 Tire *tire = [Tire new]; 137 [car setTire:(Tire *) tire atIndex:(int) i]; 138 } 139 NSLog(@"Before update car"); 140 [car print]; 141 Engine *newengine = [V8engine new]; 142 [car setEngine:(Engine *)newengine]; 143 Tire *newtire; 144 newtire = [BetterTire new]; 145 [car setTire:(Tire *)newtire atIndex:(int) 2]; 146 NSLog(@"After update car"); 147 [car print]; 148 return 0; 149 }