Program to find the day of the given date

Program:

#include<stdio.h>
#include<conio.h>
void main()
{
    int month[12] = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
    int date, mon, year, i, r, s = 0;
    char week[7][10];
    clrscr();
    strcpy(week[0], "Sunday");
    strcpy(week[1], "Monday");
    strcpy(week[2], "Tuesday");
    strcpy(week[3], "Wednesday");
    strcpy(week[4], "Thursday");
    strcpy(week[5], "Friday");
    strcpy(week[6], "Saturday");
    printf("Enter a valid date (dd/mm/yyyy) : ");
    scanf("%d / %d / %d", &date, &mon, &year);
    if( (year / 4 == 0) && (year % 400 == 0) && (year % 100 != 0))
    month[1] = 29;
    for(i = 0 ; i < mon - 1 ; i++)
    s = s + month[i];
    s = s + (date + year + (year / 4) - 2);
    s = s % 7;
    printf("\nThe day is : %s", week[s]);
    getch();
}

Output:

Enter a valid date (dd/mm/yyyy) : 02/11/1977
The day is : Wednesday