通过日期计算星期函数（C语言版）

测试源代码：

#include <stdio.h>int getDayOfWeek(int year, int month, int day) {if (month < 3) {month += 12;year--;}int q = day;int m = month;int K = year % 100;int J = year / 100;int dayOfWeek = (q + 13 * (m + 1) / 5 + K + K / 4 + J / 4 - 2 * J) % 7;// Adjust for C's modulo operation that can result in negative valuesif (dayOfWeek < 0) {dayOfWeek += 7;}// 0 corresponds to Saturday, 1 to Sunday, ..., 6 to Fridayreturn dayOfWeek;
}int main() {int year, month, day;// Input dateprintf("Enter year: ");scanf("%d", &year);printf("Enter month: ");scanf("%d", &month);printf("Enter day: ");scanf("%d", &day);// Calculate day of weekint dayOfWeek = getDayOfWeek(year, month, day);// Display the resultswitch (dayOfWeek) {case 0:printf("Saturday\n");break;case 1:printf("Sunday\n");break;case 2:printf("Monday\n");break;case 3:printf("Tuesday\n");break;case 4:printf("Wednesday\n");break;case 5:printf("Thursday\n");break;case 6:printf("Friday\n");break;default:printf("Invalid day\n");break;}return 0;
}

注意：其中0表示星期六，1表示星期天，以此类推。