C++由年月日确定周几 C++基于蔡基姆拉尔森计算公式实现由年月日确定周几的方法示例

#include <iostream>
#include <string>
using namespace std;
int whatday(int y, int m, int d) {
  // 返回正确的星期。用 0 - 6 表示 星期 1 - 7
  if(m==1||m==2)
  {
    y--;
    m+=12;
  }
  return(d+2*m+3*(m+1)/5+y+y/4-y/100+y/400)%7;
}
string weekday[7] = {"Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday", "Sunday"};
int main() {
  int y, m, d;
  cin >> y >> m >> d;
  cout << weekday[whatday(y, m, d)] << endl;
  return 0;
}