iOS -- 字符串倒序输出

 

    NSString *string=@"123456789";

    NSMutableString *str =[NSMutableString string];

    for (int a=string.length-1; a>=0; a--)

    {

        unsigned short st = [string characterAtIndex:a];

        [str insertString:[NSString stringWithFormat:@"%c",st] atIndex:str.length];

    }

    NSLog(@"str======%@",str);