一、概念

二、代碼

#import <Foundation/Foundation.h>
#pragma mark 類

#pragma mark main函數(shù)

@interface Person : NSObject
{
    @public
    int age;
    double  height;
}
- (void)printf;
@end

void text1(int newAge, double newHeight);
void text2(Person *newP);
void text3(Person *newP);
void text4(Person *newP);

int main()
{
    Person *p = [Person new];
    p->age = 10;
    p->height = 1.5f;
    
    text1(p->age, p->height); // 10 1.5f
    [p printf]; // 10 1.5f
    
    text2(p);   // 指針,地址
    [p printf]; // 20, 1.71

#warning 主要text3復(fù)雜一點 因為內(nèi)部 開辟了一塊新的存儲空間 需要看清楚指向誰
    text3(p);   // 指針,地址
    [p printf]; // 20 1.71
    
    text4(p);   // 指針,地址
    [p printf]; // 33, 1.99
}

@implementation Person

- (void)printf
{
    NSLog(@"年齡 = %i,身高 = %f",age,height);
}

@end

void text1(int newAge, double newHeight)
{
    newAge = 30;
    newHeight = 1.6f;
}
// Person *newP = p
void text2(Person *newP)
{
    newP->age = 20;
    newP->height = 1.71f;
}
void text3(Person *newP)
{
    Person *p2 = [Person new];
    p2-> age = 40;
    p2-> height = 1.8f;
    newP = p2;
    newP->age = 30;
}
void text4(Person *newP)
{
    Person *p2 = newP;
    p2 -> age = 50;
    p2 -> height = 1.99f;
    newP -> age = 33;
}

image.png

log

 年齡 = 10,身高 = 1.500000
年齡 = 20,身高 = 1.710000
年齡 = 20,身高 = 1.710000
年齡 = 33,身高 = 1.990000