NSMutableArray和NSArray

        //数组属于集合类型#pragma mark ----------不可变数组        /*         1.oc中的数组只能存储对象类型         2.不能存储基本数据类型（int， NSInteger)         3.数组对象中可以同时存储不同类型的对象         4.数组元素是有序的，下标从0开始         5.nil是数组的结束标志         6.oc中数组越界，必然崩溃         7.如果是整体输出，有汉字的话，输出的Unicode编码，单独打印就不会出现这种情况         */        //第一种创建方式        NSArray *array1 = [[NSArray alloc]initWithObjects:@"重庆",@"asdf", nil];        NSLog(@"%@",array1);        //第二种创建方式        NSArray *array2 = [NSArray arrayWithArray:array1];        NSLog(@"array2 = %@",array2);        //获取元素的个数        NSUInteger n = [array2 count];        NSLog(@"n = %lu",n);        //根据下标获取元素        NSLog(@"%@",[array2 objectAtIndex:1]);        //根据元素获取下标        NSLog(@"%lu",[array2 indexOfObject:@"重庆"]);        //语法糖，不需要nil结尾,只能使用在不可变的数组中        NSArray *array3 = @[@"1",@"2",@"3"];        //访问数组        NSLog(@"%@",array3[2]);#pragma mark ---------------可变数组        //创建一个空得数组对象        NSMutableArray *marray = [NSMutableArray array];        NSLog(@"%@",marray);        NSMutableArray *marray2 = nil;        NSLog(@"marray2 = %@",marray2);        //添加        [marray addObject:@"hahah"];        [marray addObject:@"hahah"];        [marray addObject:@"hahah"];        [marray addObject:@"hahah"];        [marray addObject:@"hahah"];        [marray addObject:@"biubiubiu"];        NSLog(@"marray = %@",marray);        //插入        [marray insertObject:@"40" atIndex:0];        NSLog(@"marray = %@",marray);        //交换数组中元素的位置        [marray exchangeObjectAtIndex:1 withObjectAtIndex:2];         NSLog(@"marray = %@",marray);        //替换        [marray replaceObjectAtIndex:0 withObject:@"bengbeng"];         NSLog(@"marray = %@",marray);        //移除,把所有的相同的都删了        [marray removeObject:@"biubiu"];        NSLog(@"marray = %@",marray);        [marray removeLastObject];        NSLog(@"marray = %@",marray);        [marray removeObjectAtIndex:2];        [marray removeObject:@"hahah"];        NSLog(@"marray = %@",marray);        [marray removeAllObjects];        NSLog(@"marray = %@",marray);        Book *b1 = [Book bookWithName:@"数据结构" price:20.00];         Book *b2 = [Book bookWithName:@"计算机组成" price:23.00];         Book *b3 = [Book bookWithName:@"计算机网络" price:27.00];         Book *b4 = [Book bookWithName:@"深入内核" price:25.00];         Book *b5 = [Book bookWithName:@"网络管理" price:24.00];         Book *b6 = [Book bookWithName:@"网络安全" price:22.00];        NSMutableArray *libray = [NSMutableArray arrayWithObjects:b1,b2,b3,b4,b5,b6, nil];        NSString *searchName = @"网络管理";        for (int i = 0; i < libray.count; i++) {            Book *b  = libray[i];            if ([[b name] isEqualToString:searchName]) {                [b setPrice:50];                 [b introduce];            }        }        for (int i = 0; i < libray.count; i++) {            Book *b  = libray[i];                [b introduce];        }        //添加一本书        Book *newbook = [Book bookWithName:@"资本论" price:99.99];        [libray addObject:newbook];        NSLog(@"%@",libray);        //删除书籍        [libray removeObject:@"数据结构"];//        [libray removeObjectAtIndex:1];#pragma mark ---------NSNumber NSValbe        //NSNumber 实现数值和对象的转换        NSNumber *number = [NSNumber numberWithInt:10];        NSLog(@"%@",number);        NSNumber *numb1 = [NSNumber numberWithFloat:19.99];        NSLog(@"%@",numb1);         float n1 = [numb1 floatValue];        NSLog(@"%.3f",n1);        //nsvalbe 实现结构体和对象的转换     nsvalue 是nsnumber的父类        NSRange range = NSMakeRange(1, 2);        NSValue *value = [NSValue valueWithRange:range];    }    }