//	BCD
#include"stdio.h"

int toBCD(int x){
	if (x < 100){
		int a = ((x / 10) << 4);
		int b = (x % 10);
		return (a + b);
	}
	else{
		fprintf(stderr, "Number greater than 99 passed to toBCD()");
	}
}

int fromBCD(int x){
	int a = ((x >> 4) * 10);
	int b = (x & 0xF);
	return (a + b);
}

int main (){
	int i = 39;
	printf("1. %d\n2. %d\n3. %d\n", i, toBCD(i), fromBCD(toBCD(i)));
	return 0;
}