练习

{
@public
    int age;
    double height;
}
- (void)print;
@end
//  int newAge = 10, double newHeight = 1.5
void test1(int newAge, double newHeight);
void test2(Person *newP);
void test3(Person *newP);
void test4(Person *newP);

int main(int argc, const char * argv[]) {
    @autoreleasepool {
        Person *p = [Person new];
        p->age = 10;
        p->height = 1.5f;
        test1(p->age, p->height); // 10, 1.5
        [p print]; // 10, 1.5
        
        test2(p); // 指针, 地址
        [p print]; // 20, 1.7
        
        test3(p); // 指针, 地址
        [p print]; // 20, 1.7
        
        test4(p); // 指针, 地址
        [p print]; // 60, 1.9
     //对象的传递就是指针的传递
        
    }
    return 0;
}

@implementation Person
- (void)print
{
    NSLog(@"年龄=%d，身高=%f", age, height); // 10, 1.5
}
@end
void test1(int newAge, double newHeight){
    newAge = 30;
    newHeight = 1.6;
}
void test2(Person *newP)
{
    newP->age = 20;
    newP->height = 1.7;
}
void test3(Person *newP)
{
    Person *p2 = [Person new];
    p2->age = 40;
    p2->height = 1.8;
    newP = p2;
    
    newP->age = 30;
}
void test4(Person *newP)
{
    Person *p2 = newP;
    p2->age = 50;
    p2->height = 1.9;
    newP->age = 60;
}