zeller.cpp

// C++ program to Find the Day
// for a Date
#include <cmath>
#include <cstring>
#include <iostream>
using namespace std;

int Zellercongruence(int day, int month, int year) {
    if (month == 1) {
        month = 13;
        year--;
    } if (month == 2) {
        month = 14;
        year--;
    }
    int q = day;
    int m = month;
    int k = year % 100;
    int j = year / 100;
    int h = q + 13 * (m + 1) / 5 + k + k / 4 +
            j / 4 + 5 * j;
    h = h % 7;
    switch (h) {
    case 0:
        cout << "Saturday \n";
        break;
    case 1:
        cout << "Sunday \n";
        break;
    case 2:
        cout << "Monday \n";
        break;
    case 3:
        cout << "Tuesday \n";
        break;
    case 4:
        cout << "Wednesday \n";
        break;
    case 5:
        cout << "Thursday \n";
        break;
    case 6:
        cout << "Friday \n";
        break;
    }
    return 0;
}

// Driver code
int main() {
    Zellercongruence(11, 11, 2022); // date (dd/mm/yyyy)
    return 0;
}