ios 两个时间差多少天时分

计算两个时间差：

NSDateFormatter *date = [[NSDateFormatter alloc]init];

    [datesetDateFormat:@"yyyy/MM/dd HH:mm:ss"];

 NSDate*startD = [datedateFromString:time1];

    NSDate*endD = [datedateFromString:time2];

    NSTimeInterval start = [startD timeIntervalSince1970]*1;

    NSTimeInterval end = [endD timeIntervalSince1970]*1;

    NSTimeIntervalvalue = end - start;

    NSString*days = [NSStringstringWithFormat:@"%d",(int)value / (24*3600)];

    NSString*hours = [NSStringstringWithFormat:@"%d",(int)(value-days.integerValue*24*3600) /  3600];

    NSString*minutes = [NSStringstringWithFormat:@"%d",(int)value /60%60];

    NSString*format_time = [NSStringstringWithFormat:@"距离截止：%@天%@时%@分",days,hours,minutes];