6.地址,Block,SEL,多态

1.main.m文件

int maxValue(int a,int b){

return a > b ? a : b;

}

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

@autoreleasepool {

//---------------------------//五大内存地址---------------------------
int a = 10;
NSLog(@"%p",&a);//栈--->0x7fff5fbff86c

int *p = malloc(40);
NSLog(@"%p",p);//堆--->0x100201ac0

static int b = 10;
NSLog(@"%p",&b);//静态区--->0x1000023e0

char *string = "iPhone";
NSLog(@"%p",string);//常量区--->0x100001f75

NSLog(@"%p",maxValue);//代码区--->0x100001cd0

//---------------------------//block数据类型---------------------------
//block弥补了指向函数的指针不能够直接保存一个函数体(代码块),相当与一个匿名的函数,等号前面是代码块的定义,后面是实现内容,有四种形式
//1.无参数无返回值
void (^block)() = ^{
NSLog(@"暴风雨来了");
};
block();//--->暴风雨来了
//block自己不会执行,必须调用才会执行block大括号里面的代码段

//2.有参数无返回值
void (^maxBlock)(int,int) = ^(int a,int b){
int max = a > b ? a : b;
NSLog(@"%d",max);
};
maxBlock(6,9);//--->9
//void (^)(int,int)是block的类型,他的名字是block,我们也可以通过名进行调用

void (^arrBlock)(NSArray *) = ^(NSArray *arr){
for (NSString *str in arr) {
NSLog(@"%@",str);
}
};
NSArray *arr = @[@"1",@"2",@"3"];
arrBlock(arr);//--->1,2,3

//3.无参数有返回值
int (^oneBlock)() = ^{
return 10;
};
NSLog(@"%d",oneBlock());//block调用没有参数也得有()--->10

//4.有参数有返回值
int (^mBlock)(int,int) = ^(int a,int b){
return a > b ? a : b;
};
NSLog(@"%d",mBlock(3,8));//--->8

NSString *(^ablcok)(NSArray *,NSInteger) = ^(NSArray *arr,NSInteger index){
return arr[index];
};
NSLog(@"%@",ablcok(@[@"1",@"2"],1));//--->2

//5.如果想改变block代码块之外的变量值,就必须在之前加入__block关键字
__block int x = 100;
int (^sumBlock)(int a,int b) = ^int(int a,int b){
int result = a + b;
x = result;
return result;
};
//block自己不会执行,必须调用才会执行block大括号里面的代码段
NSLog(@"x = %d",x);//100
NSLog(@"a+b=%d",sumBlock(11,14));//25
NSLog(@"x = %d",x);//25
//当在开发中一个方法有多种实现的时候,如果不确定用哪种方法更好,我们可以考虑把方法中的一个参数定义成block方式
Calculate *cal = [[Calculate alloc]init];
int sum = [cal calculateWithNumber1:10 andNumber2:20 andCalculate:sumBlock];
NSLog(@"a + b = %d",sum);//30

//通过用系统的block对数组进行遍历(用法用回车)
NSArray *array = [NSArray arrayWithObjects:@"1",@"2",@"3",@"4", nil];
[array enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL *stop) {
NSLog(@"%@",obj);//--->1,2,3,4
}];

//数组排序数组对字符串的排序
//不可变数组
NSArray *arr1 = @[@"zhan",@"wuhe",@"liusansan",@"wangjumin",@"hehehd"];
//SEL叫方法选择器,他是方法选择器的类型
NSArray *arra = [arr1 sortedArrayUsingSelector:@selector(compare:)];
NSLog(@"%@",arra);//--->hehehd,liusansan,wangjumin,wuhe,zhan

//可变数组排序
NSMutableArray *array1 = [NSMutableArray arrayWithObjects:@"zhan",@"wuhe",@"liusansan",@"wangjumin",@"hehehd",nil];
[array1 sortUsingSelector:@selector(compare:)];
NSLog(@"---%@",array1);//--->hehehd,liusansan,wangjumin,wuhe,zhan

//对对象进行排序
//新建四个人的对象
Person *per1 = [Person baseWithName:@"zhangxiaoyun" sex:@"nv"];
Person *per2 = [Person baseWithName:@"wangya" sex:@"nv"];
Person *per3 = [Person baseWithName:@"liushuxi" sex:@"nan"];
Person *per4 = [Person baseWithName:@"shiyu" sex:@"nv"];
NSArray *arr2 = @[per1,per2,per3,per4];
NSArray *newArr = [arr2 sortedArrayUsingComparator:^NSComparisonResult(Person *obj1, Person *obj2) {
return -[obj1.name compare:obj2.name];//加个-号变为降序排列
}];
for (Person *per in newArr) {
NSLog(@"%@",per.name);
}

NSMutableArray *arr3 = [NSMutableArray arrayWithObjects:per1,per2,per3,per4,nil];
[arr3 sortUsingComparator:^NSComparisonResult(id obj1, id obj2) {
Person *per11 = (Person *)obj1;
Person *per22 = (Person *)obj2;
return [per11.name compare:per22.name];
}];
for (Person *per in arr3) {
NSLog(@"%@",per.name);
}

//---------------------------//SEL数据类型------------------------------------
Calculate *person = [[Calculate alloc]init];
//[person eat];//消息机制
//使用@select就能够把一个方法包装成SEL数据类型
SEL s1 = @selector(eat);
[person performSelector:s1];
//上面两句合并等价于下面一句
[person performSelector:@selector(eat)];

SEL s2 = @selector(call:);
[person performSelector:@selector(call:) withObject:@"15382006306"];

SEL s3 = @selector(fingName);
NSString *str = [person performSelector:s3];
NSLog(@"%@",str);

}
return 0;

}

2.Calculate.h文件

#import <Foundation/Foundation.h>
typedef int (^calculateBlock)(int a,int b);

@interface Calculate : NSObject

- (int)calculateWithNumber1:(int)number1 andNumber2:(int)number andCalculate:(calculateBlock)calculate;
- (void)eat;
- (void)call:(NSString *)number;
-(NSString *)fingName;

//简单的多态-------------------------------------------->
@property(nonatomic,copy)NSString *name;
@property(nonatomic,copy)NSString *sex;
- (id)initWithName:(NSString *)name sex:(NSString *)sex;
+ (id)baseWithName:(NSString *)name sex:(NSString *)sex;

@end

2.Calculate.m文件

#import "Calculate.h"

@implementation Calculate

- (int)calculateWithNumber1:(int)number1 andNumber2:(int)number2 andCalculate:(calculateBlock)calculate
{   //经常变化的功能,在设计当中叫做封装变化
return calculate(number1,number2);
}

- (void)eat
{
NSLog(@"吃东西");
}
- (void)call:(NSString *)number
{
NSLog(@"打电话给:%@",number);
}
-(NSString *)fingName
{
return @"找到了曹颖";
}

//简单的多态-------------------------------------------->
- (id)initWithName:(NSString *)name sex:(NSString *)sex
{
self = [super init];
if (self) {
self.name = name;
self.sex = sex;
}
return self;
}

+ (id)baseWithName:(NSString *)name sex:(NSString *)sex
{
//多态的方式完成对象的创建
id obj = [[[self class] alloc] initWithName:name sex:sex];
return obj;
}

@end