#import <Foundation/Foundation.h>

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

    @autoreleasepool {
        
        NSDate *date = [NSDate date];
        NSLog(@"date = %@",date);
        
        //距离现在时间多少s之后的时间
        NSDate *date2 = [NSDate dateWithTimeIntervalSinceNow:60];
        NSLog(@"date2 = %@",date2);
        
        //时间戳:距离1970/01/01 00:00:00之后的秒数
        //距离1970/01/01 这个时间点100s之后的时间
        NSDate *date3 = [NSDate dateWithTimeIntervalSince1970:100];
        NSLog(@"date3 = %@",date3);
        
        //距离date3之后100s的时间
        NSDate *date4 = [NSDate dateWithTimeInterval:100 sinceDate:date3];
        NSLog(@"date4 = %@",date4);
        
        //遥远的未来
        NSDate *date5 = [NSDate distantFuture];
        NSLog(@"date5 = %@",date5);
        
        //遥远的过去
        NSDate *date6 = [NSDate distantPast];
        NSLog(@"date6 = %@",date6);
        
        NSDate *date7 = [NSDate date];
        //返回以当前时间为基准，然后过了1000秒的时间
        NSDate *date8 = [NSDate dateWithTimeIntervalSinceNow:1000];
        //以date7为基准时间，返回实例保存的时间与date7的时间间隔
        double time = [date8 timeIntervalSinceDate:date7];
        NSLog(@"time = %f",time);
        //返回以当前NSDate对象为基准，偏移1000秒后得到的新NSDate对象
        NSDate *date9 = [date8 dateByAddingTimeInterval:1000];
        NSLog(@"date7--date9 = %@--%@",date7,date9);
        
        //与date9比较，返回较早的那个日期
        NSDate *date10 = [date7 earlierDate:date9];
        //与date9比较，返回较晚的那个日期
        NSDate *date11 = [date7 laterDate:date9];
        NSLog(@"date10--date11 = %@--%@",date10,date11);
        
        NSDate *dateNow = [NSDate date];
        NSDateFormatter *df = [[NSDateFormatter alloc] init];
        //设置格式
        df.dateFormat = @"yyyy-MM-dd HH:mm:ss";
        //NSDate转NSString
        NSString *dateTime = [df stringFromDate:dateNow];
        NSLog(@"dateTime = %@",dateTime);
        
        NSString *dateStr = @"2015-03-10 00:00:00";
        //NSString转NSDate
        NSDate *date12 = [df dateFromString:dateStr];
        NSLog(@"date12 = %@",date12);
    }
    return 0;
}