#include<stdio.h>

void dec2bin(int n);

int hexDisplay(int n);

void dec2hex(int n);

void alphabet();

int exceptHola(int n);

int main(){
	int n, choice;
	printf("Exchange Tool:\n1. Decimal to Binary\n2. Decimal to Hexadecimal\n3. Print all alphabet characters except HOLAhola.\nwhat is your choice?>");
	tryAgain: scanf("%d", &choice);
	printf("\n----------------------\n");
	
	switch (choice){
		case 1:{
			printf("Please enter your decimal to convert>");
			scanf("%d", &n);
			dec2bin(n);
			break;
		}
		case 2:{
			printf("Please enter your decimal to convert>");
			scanf("%d", &n);
			dec2hex(n);
			break;
		}
		case 3:{
			alphabet(n);
			break;
		}
		default:{
			printf("Try again, bro>");
			goto tryAgain;
		}
	}
	return 0;
}

void dec2bin(int n){
	int sodu, i = 0;
	int bit[100];
	printf("\nThe binary representation of the number %d is: ", n);
	while(n > 0){	
		sodu = n % 2;
		bit[i] = sodu;
		i++;
		n /= 2;
	}
	while(i > 0){	
		i--;
		printf("%d", bit[i]);
	}
}

int hexDisplay(int n){
	if(n > 9) return n + 55;
	return n + 48;
}

void dec2hex(int n){
	int sodu, i = 0;
	int hex[100];
	printf("\nThe hexadecimal representation of the number %d is: ", n);
	while(n > 0){	
		sodu = n % 16;
		hex[i] = sodu;
		i++;
		n /= 16;
	}
	while(i > 0){	
		i--;
		printf("%c", hexDisplay(hex[i]));
	}
}

int exceptHola(int n){
	if(n == 'H') return 1;
	if(n == 'O') return 1;
	if(n == 'L') return 1;
	if(n == 'A') return 1;
	if(n == 'h') return 1;
	if(n == 'o') return 1;
	if(n == 'l') return 1;
	if(n == 'a') return 1;
	return 0;
}

void alphabet(){
	int i = 64;
	printf("\nupper case:\t");
	do{
		i++;
		if(i == 97) printf("\nlower case:\t");
		if(i > 90 && i < 97) continue;
		if(exceptHola(i)) continue;
		printf("%c ", i);
	}while(i < 122);
}