public override bool LoadNodeFromString(ref string st, ref int pos)
{
bool res = true;
if (pos >= st.Length)
{
res = false;
}
else
if (st[pos] != '(')
{
res = false;
}
else
{
++pos;
while (pos < st.Length && st[pos] == ' ')
{
++pos;
}
left = OneNode.NewNode(ref st, ref pos);
if (left == null)
{
res = false;
}
else
{
while (pos < st.Length && st[pos] == ' ')
{
++pos;
}
int p = Array.IndexOf(Sings, st[pos]);
if (pos == st.Length || p == -1 || p == 4)
{
res = false;
}
else
{
sign = (Sign)p;
// MessageBox.Show("Sign in reading = " + st[pos] + " p = " + p+" si = "+sign);
++pos;
right = OneNode.NewNode(ref st, ref pos);
if (right == null)
{
res = false;
}
else
{
while (pos < st.Length && st[pos] == ' ')
{
++pos;
}
if (pos == st.Length || st[pos] != ')')
{
res = false;
}
else
{
++pos;
}
// MessageBox.Show("res = " + res);
}
}
}
}
return(res);
}
bool TryClear(ref OneNode R, ref int count)
{
bool res = true;
if (R != null)
{
OneNode l = R.left;
OneNode r = R.right;
if (Root is SignNode)
{
if (l == null || r == null)
{
return(false);
}
Sign s = ((SignNode)R).Sign;
// MessageBox.Show("Here, s = " + s.ToString());
if (l is IntNode && r is IntNode)
{
int left = ((IntNode)l).Finfo;
int right = ((IntNode)r).Finfo;
switch (s)
{
case Sign.mult:
R = new IntNode(left * right);
++count;
break;
case Sign.add:
R = new IntNode(left + right);
++count;
break;
case Sign.divide:
if (right == 0)
{
return(false);
}
else
{
R = new IntNode(left / right);
}
++count;
break;
case Sign.subst:
R = new IntNode(left - right);
++count;
break;
default: return(false);
}
}
else
{
switch (s)
{
case Sign.add:
if (l is IntNode && ((IntNode)l).Finfo == 0)
{
R = R.right;
++count;
TryClear(ref R, ref count);
}
else
if (r is IntNode && ((IntNode)r).Finfo == 0)
{
R = R.left;
++count;
TryClear(ref R, ref count);
}
else
{
TryClear(ref R.left, ref count);
TryClear(ref R.right, ref count);
}
break;
case Sign.divide:
if (l is IntNode && ((IntNode)l).Finfo == 0)
{
R = new IntNode(0);
++count;
}
else
if (r is IntNode)
{
if (((IntNode)r).Finfo == 0)
{
return(false);
}
else
if (((IntNode)r).Finfo == 1)
{
R = R.left;
++count;
TryClear(ref R, ref count);
}
}
else
{
TryClear(ref R.left, ref count);
TryClear(ref R.right, ref count);
}
break;
case Sign.mult:
if (l is IntNode)
{
if (((IntNode)l).Finfo == 0)
{
++count;
R = new IntNode(0);
}
else
if (((IntNode)l).Finfo == 1)
{
R = R.right;
++count;
TryClear(ref R, ref count);
}
}
else
if (r is IntNode)
{
if (((IntNode)r).Finfo == 0)
{
R = new IntNode(0);
++count;
}
else
if (((IntNode)r).Finfo == 1)
{
R = R.left;
++count;
TryClear(ref R, ref count);
}
}
else
{
TryClear(ref R.left, ref count);
TryClear(ref R.right, ref count);
}
break;
case Sign.subst:
if (r is IntNode && ((IntNode)r).Finfo == 0)
{
R = R.left;
++count;
TryClear(ref R, ref count);
}
else
{
TryClear(ref R.left, ref count);
TryClear(ref R.right, ref count);
}
break;
default: return(false);
}
}
}
}
return(res);
}
public SignNode(Sign c) : base()
{
sign = c;
}