void do_arith (bigint_stack& stack, const char oper) {
if (stack.size() < 2) throw ydc_exn ("stack empty");
bigint right = stack.top();
stack.pop();
DEBUGF ('d', "right = " << right);
bigint left = stack.top();
stack.pop();
DEBUGF ('d', "left = " << left);
bigint result;
switch (oper) {
case '+': result = left + right; break;
case '-': result = left - right; break;
case '*': result = left * right; break;
case '/': result = left / right; break;
case '%': result = left % right; break;
case '^': result = pow (left, right); break;
default: throw invalid_argument (
string ("do_arith operator is ") + oper);
}
DEBUGF ('d', "result = " << result);
stack.push (result);
}
void do_dup (bigint_stack& stack, const char) {
bigint top = stack.top();
DEBUGF ('d', top);
stack.push (top);
}