@interface Car : NSObject{

    @public

    int _wheels;

    int _speed;

}

- (void)run;

@end

@implementation Car

- (void)run{

    NSLog(@"%d個輪子, 速度為%d的車子跑起來了", _wheels, _speed);

}

@end

void test1(Car *newCar){

    newCar->_wheels = 5;

}

void test2(Car *newCar);

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

    Car *c1 = [[Car alloc] init];

    Car *c2 = [[Car alloc] init];

    test1(c1);

    test2(c2);

    [c1 run];

    [c2 run];

    return 0;

}

void test2(Car *newCar){

    newCar->_wheels = 4;

    newCar->_speed = 300;

}