通过分类为数组添加一个倒序的一个方法.

分类声明文件

#import <Foundation/Foundation.h>@interface NSArray (Reserve)- (NSArray *)reserve;@end

分类实现文件

#import "NSArray+Reserve.h"@implementation NSArray (Reserve)- (NSArray *)reserve{    NSMutableArray *arr = [NSMutableArray arrayWithArray:self];    for (int i = 0; i < [arr count]/2; i++) {        [arr exchangeObjectAtIndex:i withObjectAtIndex:[arr count] - i - 1];    }    return arr;}@end

主函数调用

NSArray *array = [NSMutableArray arrayWithObjects:@"aa",@"ww",@"cc",@"dd",@"bb",nil];            NSArray *newArr = [array reserve];        NSLog(@"%@", newArr);