43 lines
751 B
C
43 lines
751 B
C
#include <stdio.h>
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int date_to_day(int year, int month, int day) {
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if (month < 3) {
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month += 12;
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year -= 1;
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}
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return ((13*month+3)/5 + day + year + year/4 - year/100 + year/400) % 7;
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}
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int main() {
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int rc, year, month, day, nd;
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printf("Enter a day (yyyy-mm-dd): ");
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rc = scanf("%d-%d-%d", &year, &month, &day);
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if (rc != 3) {
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printf("Failed to parse date\n");
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return 1;
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}
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nd = date_to_day(year, month, day);
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switch (nd) {
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case 0:
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printf("Monday\n"); break;
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case 1:
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printf("Tuesday\n"); break;
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case 2:
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printf("Wednesday\n"); break;
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case 3:
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printf("Thursday\n"); break;
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case 4:
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printf("Friday\n"); break;
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case 5:
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printf("Saturday\n"); break;
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case 6:
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printf("Sunday\n"); break;
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}
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return 0;
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}
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