#include <stdio.h>
#include "numbers.h"



/* Converts the given number to its representation modulo 2*10^{SIZE} */
void number2modular(Number number)
{
	int i;

	if (number[SIZE] == 0) /* positive number */
		return;
	
	/* Subtract from 2*10^{SIZE} */
	for (i = 0; number[i] == 0; i++); /* skip zeros */

	if (i == SIZE) { /* number is -0 */
		number[SIZE] = 0; /* remove the -ve sign */
		return;
	}

	/* First non-zero digit, subtract from 10 */
	number[i] = 10 - number[i];

	/* Subtract remaining digits from 9 */
	for (i++; i < SIZE; i++)
		number[i] = 9 - number[i];

	return;
} /* end of number2modular() */


/* Adds the two numbers modulo 2*10^{SIZE} */
void add_numbers(Number num1, Number num2, Number num3)
{
	int carry; /* Stores the carry value */

	for (int i = 0, carry = 0; i <= SIZE; i++) {
		num3[i] = num1[i] + num2[i] + carry;
		if (num3[i] > 9) { /* new carry created */
			num3[i] = num3[i] - 10;
			carry = 1;
		}
		else /* no carry created */
			carry = 0;
	}

	if (num3[SIZE] == 2) { /* sum too large */
		num3[SIZE] = 0; /* Go modulo 2*10^{SIZE} */
	}
	if (num3[SIZE] == 3) { /* sum too large */
		num3[SIZE] = 1; /* Go modulo 2*10^{SIZE} */
	}

	return;
} /* end of add_numbers() */