#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>

int ktNamNhuan(int n){ // nam nhuan la nam chi het cho 400 hoac chia het cho 4 va ko chia het cho 100.
//	if(n%400==0)
//		return 1;
//	if(n%4==0){
//		if(n%100==0){
//			return 0;
//		}
//		else
//			return 1;
//	}
	
	if(n%400==0||n%4==0&&n%100!=0)
		return 1;
		
	return 0;
}

int inputCheck(char msg[], char error[], int min, int max){
	int check, num;
	char c;
	do{
		printf("%s",msg);
		check=scanf("%d%c", &num, &c);//Returns the value of an integer
		fflush(stdin);
        if(check!=2||c != '\n' || num<min || num>max){
            printf("%s",error);
            fflush(stdin);//Delete buffer
            check=0; //input is a character
        }
        else{
            check=1; //input is a number
        }
    }while(check==0);
    return num;
	
}

void charCheck(char *c1,char *c2){
	char enter;
	int check;
	do{
		check=scanf("%c%c%c", c1, c2,&enter);//Returns the value of an integer
        if(enter != '\n'||check!=3 ){
            printf("try again!!\nEnter 2 character: ");
            fflush(stdin);//Delete buffer
            check=0; //input invalid
        }
        else{
            check=1; //input valid
        }
    }while(check==0);
	
}

void menuOption(){
	int option;
	while(true){
		
	
		printf("1- Processing date data");
		printf("\n2- Character data");
		printf("\n3- Quit");
	option=inputCheck("\nEnter your choice: ","option (1-3).Try again!!\n",1,3);
	if(option==1){
		int day, month, year;
		day=inputCheck("Enter day: ","day (1-31) .try again!!\n",1,31);
		month=inputCheck("Enter month: ","month (1-12) .try again!!\n",1,12);
		year=inputCheck("Enter year: ","year (1-9999) .try again!!\n",1,9999);
		
			if(month==1||month==3||month==5||month==7||month==8||month==10||month==12){
				if(day<=31)
					printf("\n%d-%d-%d\n",day,month,year);
				else
					printf("\nDay, month, year you entered invalid\n");
			}
			else if(month==2){
				if(ktNamNhuan(year)){
					if(day<=29)
						printf("\n%d-%d-%d\n",day,month,year);
					else
						printf("Day, month, year you entered invalid\n");
				}
				else{
					if(day<=28)
						printf("\n%d-%d-%d\n",day,month,year);
					else
						printf("Day, month, year you entered invalid\n");
				}
			}else{
				if(day<=30)
					printf("\n%d-%d-%d\n",day,month,year);
				else
					printf("Day, month, year you entered invalid\n");	
			}
	}
	if(option==2){
		int i;
		char a,c;
		printf("Enter 2 character: ");
		charCheck(&a,&c);
		if(a<c){
			for(i=c;i>=a;i--){
				
				printf("%c:%d\n",i,i);
			}
		}else{
			for(i=a;i>=c;i--){
				
				printf("%c:%d\n",i,i);
			}
		}
	}
	if(option==3){
		break;
	}
	}
	
}

int main() {
	
	menuOption();
	
  return 0;
}