void CombineTerms(char[] operators)
{
foreach (EquationElement element in Stack)
{
if (element is Term)
{
((Term)element).CombineTerms(operators);
}
}
if (NeedSubTerms(operators) == false)
{
return;
}
int startIndex = 0;
int startpoint = 0;
while (startIndex < Stack.Count)
{
startIndex = FindOperator(startIndex, operators);
if (startIndex < 0)
{
return;
}
Term newterm = new Term();
newterm.Parent = this;
startIndex--;
startpoint = startIndex;
while (startIndex < Stack.Count)
{
EquationElement item = Stack[startIndex];
if (item is EquationValue)
{
newterm.Add(item);
startIndex++;
}
if (item is Operator)
{
Operator op = item as Operator;
if (op == null || operators.Contains(op.Value) == false)
{
Stack.RemoveRange(startpoint, newterm.Stack.Count);
Stack.Insert(startpoint, newterm);
break;
}
newterm.Add(item);
startIndex++;
}
if (startIndex >= Stack.Count)
{
Stack.RemoveRange(startpoint, newterm.Stack.Count);
Stack.Insert(startpoint, newterm);
return;
}
}
}
}
void CombineTopDown()
{
// ^연산자의 경우 가장 먼저 처리.
// 2^3^4 일 경우엔 2^(3^4) right -> left(top->down) 형태로 처리
char operatorCh = '^';
foreach (EquationElement element in Stack)
{
if (element is Term)
{
((Term)element).CombineTopDown();
}
}
int index = Stack.Count - 1;
while (index > 0)
{
Operator op = Stack[index] as Operator;
index--;
if (op == null || op.Value != operatorCh)
{
continue;
}
EquationElement left = Stack[index];
EquationElement right = Stack[index + 2];
Term newterm = new Term();
newterm.Parent = this;
newterm.Add(left);
newterm.Add(op);
newterm.Add(right);
// move signed to outer term
if (((EquationValue)left).Signed)
{
((EquationValue)left).Signed = false;
newterm.Signed = true;
}
Stack.RemoveRange(index, newterm.Stack.Count);
Stack.Insert(index, newterm);
}
}