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function is_leap_year (year) {
if (year % 400 == 0)
return true;
if (year % 100 == 0)
return false;
if (year % 4 == 0)
return true;
return false;
}
function days_to_date(days, year) {
if (days > 365)
return "erroneous number of days";
days += 1;
let d = [31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31];
if (is_leap_year(year))
d[1] += 1;
let month = 0;
while (days > d[month]) {
days -= d[month];
month += 1;
}
month += 1;
if (month < 10)
month = "0"+month;
if (days < 10)
days = "0"+days;
return month+'-'+days+'-'+year;
}
function fridays(year) {
let day = [ "sat", "sun", "mon", "tue", "wed", "thu", "fri" ];
let base_year = 2000;
let skip_days = year - base_year;
for (let yr = base_year; yr < year - 1; yr++)
if (is_leap_year(yr))
skip_days++;
let first_day_of_year = day[skip_days%7];
let first_fri_delta = 0;
while (day[(skip_days + first_fri_delta)%7] != 'fri')
first_fri_delta++;
let n = first_fri_delta;
let last_fridays = [];
let tmp = "01-01-1900";
while (n < 365) {
let date = days_to_date(n, year);
if (tmp.substring(0, 2) != date.substring(0, 2))
last_fridays.push(tmp);
n += 7;
tmp = date;
}
last_fridays.push(tmp);
for (let k of last_fridays)
console.log(k);
}
fridays(2024);
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