dayDifference method
Implementation
int dayDifference(int y, int m, int d) {
List<int> monL = [0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31];
int ifG = ifGregorian(y, m, d, 1);
if (1 == ifG) {
if ((y % 100 != 0 && y % 4 == 0) || (y % 400 == 0)) {
monL[2] += 1;
} else if (y % 4 == 0) {
monL[2] += 1;
}
}
//else cont.
int v = 0;
for (int i = 0; i <= (m - 1); i++) {
v += monL[i];
}
v += d;
// 換曆年 天數修正
if (y == 1582) {
if (ifG == 1) {
v -= 10;
}
if (ifG == -1) {
v = 0;
} // 1582/10/5 ~ 10/14 日期無效
}
return v;
}