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#pragma once
class BTree
{
private:
class Node
{
public:
Node *left, *right;
public:
Node() { left = right = NULL; }
double virtual Value() = 0;
static Node * Analize(const char *s, int i, int j)
{
int k;
int m, a, d;
for (k = i, m = a = -1; k < j; k++)
{
switch (s[k])
{
case '+':
case '-':
a = k;
break;
case '*':
case '/':
m = k;
break;
}
}
d = (a >= 0? a: m);
if (d >= 0) // Neu tim thay dau thi tra ve nut chua dau
{
SNode *snode = new SNode();
snode->sign = s[d];
snode->left = Node::Analize(s, i, d - 1);
snode->right = Node::Analize(s, d + 1, j);
return snode;
}
VNode *vnode = new VNode();
double v = 0.0;
double f = 10;
for (k = i; k < j; k++)
{
switch (s[k])
{
case '.':
f = 1;
break;
case ' ':
break;
default:
int d = s[k] - 48;
if (f > 1)
v = v * 10 + d;
else
v += d * (f /= 10);
}
}
vnode->val = v;
return vnode;
}
} *root;
class SNode : public Node
{
public:
char sign;
double Value()
{
double l = this->left->Value();
double r = this->right->Value();
switch (sign)
{
case '+': return l + r;
case '-': return l - r;
case '*': return l * r;
}
return l / r;
}
};
class VNode : public Node
{
public:
double val;
double Value()
{
return val;
}
};
private:
void RemoveNode(Node *node)
{
//
// insert the code here
//
}
//Function removeNode to delete a node
public:
BTree() : root(NULL) { }
~BTree()
{
this->RemoveNode(root);
}
public:
double operator()(const char * s)
{
int len = 0;
while (s[len]) len++;
this->RemoveNode(root);
this->root = Node::Analize(s, 0, len);
return root->Value();
}
};
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