迭代器不可取消引用的堆栈（表达式树）且循环无法正常工作

Question

I am trying to convert infix to postfix and prefix by using tree in c++. I pass the infix expression to the createTree function and in the code I use 2 stack node(to store the operand and operator that has been poped from the stack s) and stack s(to store the operator). The code works finely when I input expression that has same precedence operators or the first operator has higher precedence than the second one. ex: 1*2/3 or 1/2+3. But it will debug when I input expressions which the first operator has lower precedence than the second one. for example : 1+2/3. I try to debug it and found DEBUG_ERROR("iterator not dereferencable"); I try to find in the internet and all those problems related to vector which I have never used before. I hope you guys could help me

  node *CreateTree(string post)
{
node *temp, *op1 , *op2;
stack<node*> tree;
stack<char> s;
int i = 0;
while (!tree.empty())
{
    tree.pop();
}
for(i = 0; i<post.length();i++)
{
    if (post[i]==' ') continue;
    else if(IsOperand(post[i]))
    {
        node *temp = new node();
        temp->in = post[i];
        temp->left = NULL;
        temp->right = NULL;

        for(int j=i+1;j<post.length();j++)
        {
            if (IsOperand(post[j]))
            {
                temp->in+=post[j];
                i = j;
            }
            else break;
        }
        tree.push(temp);
    }
    else if(isOperator(post[i]))
    {
        while(!s.empty() && s.top()!='(' && s.top()!='{' && s.top()!='[' && !hasHigherPrecedence(post[i],s.top()))
       {
            node *op1;
            node *op2;
            op2 = tree.top();
            tree.pop();
            op1 = tree.top();
            tree.pop();
            node *temp = new node();
            temp->in = s.top();
            temp->left = op1;
            temp->right = op2;
            root = temp;
            s.pop();
            tree.push(root);
       }
        s.push(post[i]);
    }
    else if(post[i]=='(')
   {
       s.push(post[i]);
   }
   else if(post[i]==')')
   {
       while(s.top()!='('&&!s.empty())
       {
            node *op1;
            node *op2;
            op2 = tree.top();
            tree.pop();
            op1 = tree.top();
            tree.pop();
            node *temp = new node();
            temp->in = s.top();
            temp->left = op1;
            temp->right = op2;
            root = temp;
            s.pop();
            tree.push(root);
       }
       s.pop();
   }
   else if(post[i]=='[')
   {
       s.push(post[i]);
   }
   else if(post[i]==']')
   {
       while(s.top()!='['&&!s.empty())
       {
            node *op1;
            node *op2;
            op2 = tree.top();
            tree.pop();
            op1 = tree.top();
            tree.pop();
            node *temp = new node();
            temp->in = s.top();
            temp->left = op1;
            temp->right = op2;
            root = temp;
            s.pop();
            tree.push(root);
       }
       s.pop();
   }
   else if(post[i]=='{')
   {
       s.push(post[i]);
   }
   else if(post[i]=='}')
   {
       while(s.top()!='{'&&!s.empty())
       {
            node *op1;
            node *op2;
            op2 = tree.top();
            tree.pop();
            op1 = tree.top();
            tree.pop();
            node *temp = new node();
            temp->in = s.top();
            temp->left = op1;
            temp->right = op2;
            root = temp;
            s.pop();
            tree.push(root);
       }
       s.pop();
   }
   else cout<<post[i]<<" is not registered as operator or operand";
}
while (!s.empty())
{
    node *op1;
    node *op2;
    op2 = tree.top();
    tree.pop();
    op1 = tree.top();
    tree.pop();
    node *temp = new node();
    temp->in = s.top();
    temp->left = op1;
    temp->right = op2;
    root = temp;
    s.pop();
}
return root;
}

below is the functions that are called in code above

bool isOperator(char a)
{
      return(a=='+' || a=='*' || a=='^' || a=='/' ||
       a=='-' || a=='%')? true:false;
}

int getWeight(char op)
{
 int weight;
 switch(op)
{
    case '+' : case '-':
        weight = 1;
        break;
    case '*':
    case '/':
    case '%':
        weight = 2;
        break;
    case '^':
        weight = 3;
        break;

}
return weight;

}

bool hasHigherPrecedence(char a, char top)
{
   int aW = getWeight(a);
   int tW = getWeight(top);
   return (aW > tW)? true : false;
}

Answer 1

I have found my answer i just forget to insert tree.push(root)

while (!s.empty())
{
    node *op1;
    node *op2;
    op2 = tree.top();
    tree.pop();
    op1 = tree.top();
    tree.pop();
    node *temp = new node();
    temp->in = s.top();
    temp->left = op1;
    temp->right = op2;
    root = temp;
    tree.push(root);//I forgot this
    s.pop();
}