/* Demo of simple calendar rountine. * * Written by Cyril Hu (cyrilhu@gmail.com), public domain. */#include<stdio.h>int main(void){	int day_code, days_in_month, leap_year, day, month, flag;	do {		puts("Enter day code[0,6] and leap year code[0,1]:");		scanf("%d%d", &day_code, &leap_year);	} while(day_code < 0 || day_code > 6 || 		(leap_year != 0 && leap_year != 1));	for(month = 1; month <= 12; month++) {		switch(month) {			case 1: puts("January"); days_in_month = 31; break;			case 2:				puts("February");				days_in_month = leap_year ? 29 : 28;				break;			case 3: puts("March"); days_in_month = 31; break;			case 4: puts("April"); days_in_month = 30; break;			case 5: puts("May"); days_in_month = 31; break;			case 6: puts("June"); days_in_month = 30; break;			case 7: puts("July"); days_in_month = 31; break;			case 8: puts("August"); days_in_month = 31; break;			case 9: puts("September"); days_in_month = 30; break;			case 10: puts("October"); days_in_month = 31; break;			case 11: puts("November"); days_in_month = 30; break;			case 12: puts("December"); days_in_month = 31; break;		}		puts("Sun  Mon  Tue  Wed  Thu  Fri  Sat");		for(day = 0; day < day_code * 5; day++) 			printf(" ");		for(day = 1; day <= days_in_month; day++) {			printf("%3d", day);			if( (day + day_code) % 7 > 0 ) {				printf("  ");				flag=0;			}			else {puts(""); flag=1;}		}		if(flag)			puts("");		else 			puts("\n");		day_code = (day_code + days_in_month) % 7;	}	return 0;}