实例：写一个车的类
//类的声明部分
@interface Car : NSObject
{
int _speed; //速度
int _wheel; //轮子
}
-(void)run;
@end
//类的实现部分
@implementation Car
-(void)run{
NSLog(@"车的速度是：%i,轮子是%i",_speed,_wheel);
}
@end
//函数的存在不依赖于类
void test1(Car *_car){
_car->_speed = 120;
_car->_wheel = 2;
}
//OC的类都是数据类型，可以做参数
void test2(Car *_car){
Car *car2 = [Car new];
car2->_wheel = 4;
car2->_speed = 200;
_car = car2
_car->_speed = 220;
_car->_wheel = 6;
}
#import <Foundation/Foundation.h>
int main(){
Car *car1 = [Car new];
car1->_speed = 100;
car1->_wheel =4;
test2(car1);
[car1 run]; //实现的结果还是100 4
return 0;
}