Isn t it very clear that judging conditions is the same as getting a leap year?

Ordinary leap year: A Gregorian calendar year is a multiple of 4 and not a multiple of 100, and is an ordinary leap year. (e.g. a year is a leap year); Century leap years:

The Gregorian calendar year is a whole hundred, and it must be a multiple of 400 to be a leap year of the century (e.g., 1900 is not a leap year of the century, and 2000 is a leap year of the century);

The conditions are right, but the best; Flat operators are enclosed in parentheses.

Before 1582 A.D., the Julian calendar was implemented, that is, "every four years, there is a leap", and there is no such thing as "no leap in a hundred years".

After 1582 A.D., the Gregorian calendar was implemented, and on the basis of the original "one leap in four years", the provisions of "no leap in one hundred years" and "leap in four hundred years" were added. In other words, there are only three years after 1582, 1700, 1800 and 1900.

So, all leap years from 1000 AD to 2000 AD are:

var ss=0;

for (var i=1000;i<=2000;i+=4) {if (i==1700 ||i==1800 ||i==1900)continue;

ss++;if (ss%4==0)''

I think if you don't understand, it's best to ask your mentor or find a leader.

Leap years are hard to understand, you can look up the relevant content on the Internet.

It should not be very understandable to judge the condition to get a complaint, because judging to a leap year should also be counted.

Isn't it very understandable to judge the conditions to follow up to one year? The conditions for judging are not very well understood with leap years, because leap years are one month longer.

The conditions are not very well understood with the leap year, and when you encounter the conditions or let people say that Zhonghua, you don't understand and I don't understand, so if you want to understand, you can go to the Internet to check and understand.

The conditions for judging a leap year are as follows:

A Gregorian calendar year is a multiple of 4 and not a multiple of 100, and is an ordinary leap year. Gregorian calendar years are whole hundreds, and must be multiples of 400 to be a leap year of the century. It boils down to what is usually said: every four years; There is no leap in 100 years, and then in 400 years.

Leap years are created to compensate for the time difference between the number of days of the year and the actual orbital cycle of the earth caused by the man-made calendar. The Earth's orbit around the Sun is 365 days, 5 hours, 48 minutes and 46 seconds, which is a return year. The ordinary year of the Gregorian calendar is only 365 days, which is shorter than the return year, and the remaining time is about one day accumulated every four years, so the fourth year adds one day at the end of February, so that the length of the calendar year of that year is 366 days, and this year is a leap year.

A leap year was established to compensate for the difference between the number of days of the year and the actual rotation cycle of the earth caused by the man-made calendar. The year in which the time difference is made up is a leap year. There are 366 days in a leap year (31, 29, 31, 30, 31, 30, 30, 30, 31, 31, 31, 31, 30, 30, 30, 31, 31 and 31 in January and December).

Where there is a leap day (February 29) in the solar calendar, the leap more (the year is more than the leap year. The difference in time between the lunar calendar and the return year). Note that there is no direct correlation between leap year (noun in the Gregorian calendar) and leap month (noun in the lunar calendar), the Gregorian calendar is only divided into leap years and peaceful years, with 365 days in ordinary years and 366 days in leap years (one more day in February); There may also be a leap month in a normal year (e.g. 2017 is a common year, and the lunar calendar has a leap month and a leap month).

How to judge leap years:

1. An ordinary year is divisible by 4 and not divisible by 100, it is a leap year. (e.g. 2004 is a leap year).

2. Century years are leap years that are divisible by 400. (e.g. 2000 is a leap year, 1900 is not a leap year).

3. For a year with a large value, if the year is divisible by 3200 and divisible by 172800, it is a leap year. For example, 172800 is a leap year, and 86400 is not a leap year (because although it is divisible by 3200, it is not divisible by 172800), (this is a return year of 365 days 5h48.)'''calculated).

Causes of leap years.

The Earth's orbit around the Sun is 365 days, 5 hours, 48 minutes and 46 seconds (conjunction), which is a tropical year. The common year of the Gregorian calendar is only 365 days, which is about a few days shorter than the return year, and the remaining time is about one day accumulated every four years, so one day is added at the end of February of the fourth year, so that the length of the year becomes 366 days, and this year is the leap round next year.

In the current Gregorian calendar, there are 97 leap years every 400 years. If a leap year is calculated every four years, an average of more days are counted per year, so that after 400 years, about three more days will be calculated. Therefore, every 400 years there is a reduction of 3 leap years.

Therefore, the Gregorian calendar stipulates that when the year is an integer hundred, it must be a multiple of 400 to be a leap year; A century year that is not a multiple of 400, and even a multiple of 4 is not a leap year.

Refer to the above content: Encyclopedia - Leap Year.

If it is a multiple of 4, the year is generally a leap year; If it is not a multiple of 4, the year is generally a common year. The Gregorian calendar year is a whole hundred, and it must be a multiple of 400 to be a leap year, and vice versa is a common year.

It takes 24 hours for the Earth to rotate around the Earth, and it takes 365 days for the Earth to orbit the Sun. But in fact, this is just a more general statement, to confirm that it takes 23 hours, 56 minutes and 4 seconds for the earth to rotate around the sun, and it takes 365 days, 5 hours, 48 minutes and 46 seconds for the earth to complete one orbit around the sun.

For convenience, we have set a normal year of 365 days. However, in this way, 5 hours, 48 minutes and 46 seconds will be missing, and the difference in 4 years will be 23 hours, 15 minutes and 4 seconds, which means that 4 years will be nearly one day less. Therefore, the ancients prescribed a leap year every four years, and then added this day to the second month of the leap year to make up for the undercount.

But that creates a problem, because we take the difference of 23 hours, 15 minutes, 4 seconds, 24 hours every four years. This is equivalent to an extra 44 minutes and 56 seconds, and after 400 years, there will be about 3 extra days. Therefore, every 400 years need to be subtracted by 3 leap years, so it is divisible by 100, and those that are not divisible by 400 cannot be leap years.

Judgment of ordinary leap year: The Gregorian calendar year is a multiple of 4, which is generally a leap year. (e.g. 2004 is a leap year).

Leap year of the Annihilation of the World: The year of the Oak Calendar is a whole hundred, and it must be a multiple of 400 to be a leap year (for example, 1900 is not a leap year of the century, and 2000 is a leap year of the century).

Any year in which there is a leap day (29 days in February) in the solar calendar; Leap more (more than the year is intercalated. The difference in time between the lunar calendar and the return year). Note that there is no direct correlation between leap year (noun in the Gregorian calendar) and leap month (noun in the lunar calendar).

In the Gregorian calendar, there are only leap years and peace years, with a common year having 365 days and a leap year having 366 days (one more day in mid-February); There may also be a leap moon in a normal year (e.g., 2017 is a common year, and the lunar calendar has a leap month and a leap month in June).

There is a leap in four years, a hundred years with Zen without a leap, and a leap in four hundred years.

Meaning: A year that is not a whole hundred is a leap year as long as it is divisible by 4, and a year of a whole hundred must be divisible by 400 to be called a leap year.

You can go to the encyclopedia of leap years to see, it is very detailed.

The number of years in Common Era is divisible by 4 as leap years, but the number of years with a hundred must be divisible by 400 as leap years. Everything else is an ordinary year. February in leap years has 29 days.

For example, 1996 is a leap year, 2000 is a leap year, and a flat year has 28 days in February, 1900 is a common year, and 1997 is a common year.

Simple judgment method: look at the end of the year 2 can not be silver shouted silver divisible by 4 is the common year, divisible by 4, but the last 2 digits of the year are 0, to see the first two can be divisible by 4 is a leap year, not divisible is a common year.

The rules to be followed are:

There is a leap in four years, no leap in a hundred years, and a leap in four seepage burns in a hundred years.

2008 was a leap year and 1950 was a common year.