objective-c随机数+日期格式显示一例

//
//  LotteryEntry.h
//  lottery
//
//  Created by kinds on 15/6/25.
//  Copyright (c) 2015年 hopy. All rights reserved.
//

#import <Foundation/Foundation.h>

@interface LotteryEntry : NSObject{
NSDate *entry_date;
int first_number;
int second_number;
}

-(void)prepareRandomNumbers;
-(void)setEntryDate:(NSDate*)date;
-(NSDate *)entryDate;
-(int)firstNumber;
-(int)secondNumber;
@end

//
//  LotteryEntry.m
//  lottery
//
//  Created by kinds on 15/6/25.
//  Copyright (c) 2015年 hopy. All rights reserved.
//

#import "LotteryEntry.h"

@implementation LotteryEntry

-(id)init{
self = [super init];
if(self){
[self prepareRandomNumbers];
}
return self;
}

-(void)prepareRandomNumbers{
first_number = ((int)random()%100) + 1;
second_number = ((int)random()%100) + 1;
}

-(void)setEntryDate:(NSDate *)date{
entry_date = date;
}

-(NSDate*)entryDate{
return entry_date;
}

-(int)firstNumber{
return first_number;
}

-(int)secondNumber{
return second_number;
}

-(NSString *)description{
NSDateFormatter *df = [NSDateFormatter new];
[df setTimeStyle:NSDateFormatterShortStyle];
[df setDateStyle:NSDateFormatterMediumStyle];
return [[NSString alloc]initWithFormat:@"%@ = %d and %d",
[df stringFromDate:entry_date],first_number,second_number];
}
@end

//
//  main.m
//  lottery
//
//  Created by kinds on 15/6/24.
//  Copyright (c) 2015年 hopy. All rights reserved.
//

#import <Foundation/Foundation.h>
#import "LotteryEntry.h"

int main(int argc, const char * argv[]) {
@autoreleasepool {
NSDate *now = [NSDate new];
NSCalendar *cal = [NSCalendar currentCalendar];
NSDateComponents *to_week = [NSDateComponents new];

srandom((unsigned)time(NULL));
NSMutableArray *mary = [NSMutableArray new];
for(int i = 0;i<10;i++){
[to_week setWeekOfYear:i];
NSDate *from_now = [cal dateByAddingComponents:to_week toDate:now
options:0];
LotteryEntry *le = [LotteryEntry new];
//[le prepareRandomNumbers];
[le setEntryDate:from_now];
[mary addObject:le];
}

for(LotteryEntry *le in mary)
NSLog(@"%@",le);
}
return 0;
}