cleanup

S1/GdCP/day.c

@@ -0,0 +1,38 @@
+#include<stdio.h>
+
+// Lists to define the calendar
+char *day[7] = {"Montag", "Dienstag", "Mittwoch", "Donnerstag", "Freitag", "Samstag", "Sonntag"};
+int months[12] = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
+int leap = 29;
+
+// Check for leap year
+int isleap(int y) {
+  return ((y % 4 == 0 && y % 100 != 0) || y % 400 == 0);
+}
+
+int main() {
+  // Stating date for the 1.1.1600 is a Saturday
+  int n = 5;
+
+  // Read in the date
+  int d, m, y;
+  scanf("%d.%d.%d", &d, &m, &y);
+  // Check for errors
+  if (d < 1 || m < 1 || m > 12 || d > months[m-1] || y < 1600 || y > 4000) return 1;
+
+  // Get the number of days passed
+  for (int i = 1600; i < y; i++) {
+    if (isleap(i)) n+= 366;
+    else n += 365;
+  }
+  for (int i = 0; i < m - 1; i++) {
+    if (isleap(y)) {
+      if (i == 1) n += leap;
+      else n += months[i];
+    } else n += months[i];
+  }
+  n += d - 1;
+
+  // Print the day
+  printf("%s\n", day[n % 7]);
+}