/*?Extended?precision?integer?calculator
?*?Implements?+?*?and?^?（power?of）?operations
?*
?*?Skeleton?code?written?by?Jianzhong?Qi?March?2018
?*
?*/

#include?
#include?
#include?
#include?

#define?INT_SIZE	100	/*?max?number?of?digits?per?integer?value?*/
#define?LINE_LEN	103	/*?maximum?length?of?any?input?line?*/
#define?NUM_VARS	10	/*?number?of?different?huge?int?“variables“?*/

#define?ASN_OP		‘=‘	/*?assignment?operator?*/
#define?ECH_OP		‘?‘	/*?echo?operator?*/
#define?ADD_OP		‘+‘	/*?addition?operator?*/
#define?MUL_OP		‘*‘	/*?multiplication?operator?*/
#define?POW_OP		‘^‘	/*?power?of?operator?*/

#define?OPR1_POS	1	/*?position?of?the?first?operand?*/
#define?OPR2_POS	3	/*?position?of?the?second?operand?*/
#define?OP_POS		2	/*?position?of?the?operator?*/

#define?CH_ZERO		‘0‘	/*?character?0?*/

#define?EXIT_CMD?	“exit“	/*?command?to?exit?*/
#define?PROMPT		“>?“	/*?command?prompt?*/
#define?CMT_FLAG	‘%‘		/*?indicator?for?comment?line?*/

typedef?int?digit_t;				/*?a?decimal?digit?*/
typedef?digit_t?huge_t[INT_SIZE];	/*?one?huge?int?“variable“?*/

/*?add?your?constant?and?type?definitions?here?*/

/****************************************************************/

/*?function?prototypes?*/
void?read_line（char?*line?int?max_len）;
void?init（huge_t?vars[]?int?lens[]）;
void?echo（huge_t?vars[]?int?lens[]?int?opr1_index）;
void?assign（huge_t?vars[]?int?lens[]?int?opr1_index?char?*opr2_str）;
void?add（huge_t?vars[]?int?lens[]?int?opr1_index?char?*opr2_str）;
void?multiply（huge_t?vars[]?int?lens[]?int?opr1_index?char?*opr2_str）;
void?power（huge_t?vars[]?int?lens[]?int?opr1_index?char?*opr2_str）;

/*?add?your?function?prototypes?here?*/

/****************************************************************/

/*?main?function?controls?all?the?action?do?NOT?modify?this?function?*/
int
main（int?argc?char?*argv[]）?{
	char?line[LINE_LEN+1];		/*?to?hold?the?input?line?*/
	huge_t?vars[NUM_VARS];		/*?to?hold?10?huge?integers?*/
	int?lens[NUM_VARS];			/*?to?hold?the?length?of?the?10?vars?*/

	int?opr1_index;				/*?index?of?the?first?operand?in?command?*/
	char?op;					/*?operator?in?command?*/

	init（vars?lens）;

	while?（1）?{
		printf（PROMPT）;						/*?print?prompt?*/
		read_line（line?LINE_LEN）;			/*?read?one?line?of?command?*/

		if?（line[0]?==?CMT_FLAG）?{			/*?print?comment?in?the?test?data?*/
			printf（“%s\n“?line）;			/*?used?to?simplify?marking?*/
			continue;
		}

		if?（strcmp（line?EXIT_CMD）?==?0）?{	/*?see?if?command?is?“exit“?*/
			return?0;
		}

		opr1_index?=?line[OPR1_POS]?-?CH_ZERO;/*?first?var?number?at?line[1]?*/
		op?=?line[OP_POS];					/*?operator?at?line[2]?*/

		if?（op?==?ECH_OP）?{					/*?print?out?the?variable?*/
			echo（vars?lens?opr1_index）;
			continue;
		}

		/*?do?the?calculation?second?operand?starts?at?line[3]?*/
		if?（op?==?ASN_OP）?{
			assign（vars?lens?opr1_index?line+OPR2_POS）;
		}?else?i