Find day of week from a given date Program in C

/*P5.41 Program to find day of week from a given date*/
#include<stdio.h>
int main(void)
{
	int d,m,y,j,f,h,fh,day;
	printf("Enter date(dd/mm/yyyy): ");
	scanf("%d/%d/%d",&d,&m,&y);
	j=d;
	switch(m-1)
	{
		case 11:   j+=30;	/*Fall thru in all cases*/
		case 10:   j+=31;
		case 9:    j+=30;
		case 8:    j+=31;
		case 7:    j+=31;
		case 6:    j+=30;
		case 5:    j+=31;
		case 4:    j+=30;
		case 3:    j+=31;
		case 2:    j+=28;
		case 1:    j+=31;
	}
	if(y%100!=0 && y%4==0 || y%400==0)
		if(m>2)
			j=j+1;
	f=(y-1)/4;
	h=(y-1)/100;
	fh=(y-1)/400;
	day=(y+j+f-h+fh)%7;
	switch(day)
	{
		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;
	}
	return 0;
}/*End of main()*/