int
main(void)
{
int n1, d1; /* numerator, denominator of first fraction */
int n2, d2; /* numerator, denominator of second fraction */
char op; /* arithmetic operator + - * or / */
char again; /* y or n depending on user's desire to continue */
int n_ans, /* numerator, denominator of answer */
d_ans;
/* While the user wants to continue, gets and solves arithmetic
problems with common fractions. */
do
{
/* Gets a fraction problem */
scan_fraction(&n1, &d1);
op = get_operator();
scan_fraction(&n2, &d2);
/* Computes the result */
switch (op)
{
case '+':
add_fractions(n1, d1, n2, d2, &n_ans, &d_ans);
break;
case '-':
add_fractions(n1, d1, -n2, d2, &n_ans, &d_ans);
break;
case '*':
multiply_fractions(n1, d1, n2, d2, &n_ans, &d_ans);
break;
case '/':
multiply_fractions(n1, d1, d2, n2, &n_ans, &d_ans);
}
reduce_fraction(&n_ans, &d_ans);
/* Displays problem and result */
printf("\n");
print_fraction(n1, d1);
printf(" %c ", op);
print_fraction(n2, d2);
printf(" = ");
print_fraction(n_ans, d_ans);
/* Asks user about doing another problem */
printf("\nDo another problem? (y/n) > ");
scanf(" %c", &again);
}
while (again == 'Y' || again == 'y');
return(0);
}
static _TKN_TYPE_ scan_number(_NIL_TYPE_)
{ do
scan_store_next_ch();
while (SCAN_CHECK(digit_mask));
if (SCAN_CHECK(period_mask))
return scan_fraction();
else
if (SCAN_CHECK(exponent_mask))
return scan_exponent();
else
{ scan_terminate_text();
return _NBR_TOKEN_; }}
