OC -- 练习1

// 设计一个方法，用来和其他车比较车速，返回车速的差距

#import <Foundation/Foundation.h>

@interface Car : NSObject

@property (nonatomic, assign) int speed;

- (int)compare:(Car *)newCar;

@end

@implementation Car

- (int)compare:(Car *)newCar{

return self.speed - newCar.speed;

}

@end

int main(int argc, const char * argv[]){

Car *c1 = [[Car alloc] init];

Car *c2 = [[Car alloc] init];

c1.speed = 200;

c2.speed = 150;

int res = [c1 compare:c2];

NSLog(@"res = %d", res);

return 0;

}