oc基础复习03-OC的类02参数

先写一个Person类 Person.h

#import <Foundation/Foundation.h>

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

@end

Person.m

#import "Person.h"

@implementation Person
- (void)print
{
    NSLog(@"年龄=%d，身高=%f", age, height);
}
@end

main.m

#import <Foundation/Foundation.h>
#import "Person.h"
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);
        [p print]; //10  1.5
        
        test2(p);// 20 1.7
        [p print];
        NSLog(@"before = aft%@",p);
        test3(p);//20 1.7
        [p print];
        NSLog(@"after = %@",p);
        
        test4(p);//60 1.9
        [p print];
        
    }
    return 0;
}

void test1(int newAge, double newHeight)
{
    newAge = 10;
    newHeight = 1.6;
}

void test2(Person *newP)
{
    newP->age = 20;
    newP->height = 1.7;
}

void test3(Person *newP)
{
    NSLog(@"刚传入参数地址newP = %@", newP);
    Person *p2 = [Person new];//p2指向一个新的存储空间
    p2->age = 40;
    p2->height = 1.8;
    newP = p2;//将p2的新的储存空间指向newP 这里更改只是更改p2里面的内容 而不会对newP 原来指向的地址进行更改
    NSLog(@"newP 更改后的地址= %@", newP);
    newP->age = 30;
}

void test4(Person *newP)
{
    Person *p2 = newP; //将newp的地址赋值给p2 然后进行更改p2的内容 其实就相当于更改newP里面的内容
    p2->age = 50;
    p2->height = 1.9;
    newP->age = 60;
}

运行结果：

2015-06-30 11:11:43.933 test[40776:1124334] 年龄=10，身高=1.500000

2015-06-30 11:11:43.934 test[40776:1124334] 年龄=20，身高=1.700000

2015-06-30 11:11:43.934 test[40776:1124334] before = aft<Person: 0x100211ba0>

2015-06-30 11:11:43.935 test[40776:1124334] 刚传入参数地址newP = <Person: 0x100211ba0>

2015-06-30 11:11:43.935 test[40776:1124334] newP 更改后的地址= <Person: 0x100100330>

2015-06-30 11:11:43.935 test[40776:1124334] 年龄=20，身高=1.700000

2015-06-30 11:11:43.935 test[40776:1124334] after = <Person: 0x100211ba0>

2015-06-30 11:11:43.935 test[40776:1124334] 年龄=60，身高=1.900000