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I have to implement the lexicon class to represent text vocabularies in the form of binary search trees. The class should support the following functions, which I must implement:
<pre>classlexicon {
public:
  lexicon()
  ~lexicon();
  void insert(const string &s);
  int lookup(const string &s) const;
  int depth(const string &s) const;
  void replace(const string &s1, const string &s2);
  friend ostream &operator<< (ostream &out, const lexicon &l);
};

The insert (s) method will insert the word s into the tree.

The lookup method (s) will look for the word s in the tree and return the occurrence frequency. The result will be 0 (zero) if the word does not exist in the tree.

The depth (s) method will search for the word s in the tree, as will lookup. If it does not exist, it will return −1. But if it exists, it will return the depth at which the node containing it in the tree is located, ie the length of the path from the root to this node. We assume that the root of the tree is at a depth of 0 (zero).

The replace method (s1, s2) will replace all occurrences of the word s1 with an equal number of occurrences of the word s2. If s1 does not exist in the tree, then nothing will happen. If there is also the number of occurrences is k> 0, then s1 will be deleted and the word s2 will be searched. If it does not exist, it will be entered with a frequency of k. But if there is, then the frequency of its occurrence will be informed accordingly (it will increase by k).

When deleting a word from the dictionary (done indirectly by the replace method), if a node with two non-empty children is deleted, then the deleted node is replaced by the one containing the immediately smaller word. If a node that has a non-empty child is deleted, then it is replaced by its child.

Dictionaries should be printed in alphabetical order, with the words followed by their frequency.

An example is:
<pre>int main() { 
    lexicon l; 
    l.insert("the"); 
    l.insert("boy"); 
    l.insert("and"); 
    l.insert("the"); 
    l.insert("wolf"); 
    cout << "The word 'the' is found " << l.lookup("the") << " time(s)" << endl; 
    cout << "The word 'and' is found at depth " << l.depth("and") << endl; 
    cout << l; 
    l.replace("and", "dummy"); 
    cout << "After replacement: \n"; 
    cout << l; 
    cout << "Now the word 'and' is found at depth " << l.depth("dummy") << endl; 
    l.replace("boy", "dummy"); 
    cout << "After replacement: \n"; 
    cout << l; 
    cout << "Now the word 'and' is found at depth " << l.depth("dummy") << endl; 
    l.replace("the", "dummy"); 
    cout << "After replacement: \n"; 
    cout << l; 
    cout << "Now the word 'and' is found at depth " << l.depth("dummy") << endl; 
    l.replace("wolf", "dummy"); 
    cout << "After replacement: \n"; 
    cout << l; 
    cout << "Now the word 'and' is found at depth " << l.depth("dummy") << endl; 
    return 0; 
}


This must print:
and 1
boy 1
the 2
wolf 1
and is now found 1 time(s) at depth 2
boy is now found 1 time(s) at depth 1
the is now found 2 time(s) at depth 0
wolf is now found 1 time(s) at depth 1
dummy is now found 0 time(s) at depth -1
wolf is now found 1 time(s) at depth 1
dummy is now found 1 time(s) at depth 2
wolf is now found 1 time(s) at depth 1
dummy is now found 2 time(s) at depth 1
wolf is now found 1 time(s) at depth 1
dummy is now found 4 time(s) at depth 0
wolf is now found 0 time(s) at depth -1
dummy 5
but my code prints:
and 1
boy 1
the 2
wolf 1
and is now found 1 time(s) at depth 2
boy is now found 1 time(s) at depth 1
the is now found 2 time(s) at depth 0
wolf is now found 1 time(s) at depth 1
dummy is now found 0 time(s) at depth -1
wolf is now found 1 time(s) at depth 1
dummy is now found 1 time(s) at depth 2
wolf is now found 1 time(s) at depth 1
dummy is now found 2 time(s) at depth 1
wolf is now found 1 time(s) at depth 1
dummy is now found 6 time(s) at depth 0
wolf is now found 0 time(s) at depth -1
dummy 4
dummy 7
.

What I have tried:

<pre>#include <iostream>  
#include <queue>  
using namespace std;  
  
struct node {  
    int freq;  
    string word;  
    node *left, *right;  
  
    node(const string &new_word) {  
        freq = 1;  
        this->word = new_word;  
        left = right = nullptr;  
    }  
};  
  
node* search(node* tree, const string &key) {  
        if(tree == nullptr) {  
            return tree;  
        }  
        if(tree->word == key) {  
            return tree;  
        }  
        else if(tree->word < key) {  
            return search(tree->right, key);  
        }  
        else {  
            return search(tree->left, key);  
        }  
}  
  
class lexicon {  
public:  
    node *root;  
    void Insert(const string &w, node* tree) {  
        if(w == tree->word) {  
            tree->freq++;  
            return;  
        }  
        if(w < tree->word) {  
            if(tree->left == nullptr) {  
                tree->left = new node(w);  
            }  
            else {  
                this->Insert(w, tree->left);  
            }  
        }  
        else {  
            if(tree->right == nullptr) {  
                tree->right = new node(w);  
            }  
            else {  
                this->Insert(w, tree->right);  
            }  
        }  
    }  
    int Look_up(const string &w, node* tree) const{  
        if(tree == nullptr) {  
            return 0;  
        }  
        else if(w == tree->word) {  
            return tree->freq;  
        }  
        else if(w < tree->word) {  
            return this->Look_up(w, tree->left);  
        }  
        else {  
            return this->Look_up(w, tree->right);  
        }  
    }  
  
    int Depth(const string &w, node* tree, int &deep) const{  
          
        if(tree == nullptr) {  
            return -1;  
        }  
        if(tree->word == w) {  
            return deep;  
        }  
        else if(w > tree->word) {  
            deep++;  
            return Depth(w, tree->right, deep);  
        }  
        else {  
            deep++;  
            return Depth(w, tree->left, deep);  
        }  
    }  
    void Replace(const string &s1, const string &s2, node*& tree) {  
  
        if(tree == nullptr) {  
            return;  
        }  
        else if(s1 == tree->word && tree != root) {  
            node* to_s2 = search(root, s2);  
            if(to_s2 == nullptr) {  
                this->insert(s2);  
                node* new_to_s2 = search(root, s2);  
                new_to_s2->freq += tree->freq-1;  
            }  
            else {  
                to_s2->freq += tree->freq;  
            }  
            if(tree->left == nullptr && tree->right == nullptr) {  
                tree = nullptr;  
            }  
            else if(tree->left != nullptr && tree->right == nullptr) {  
                tree = move(tree->left);  
            }  
            else if(tree->left == nullptr && tree->right != nullptr) {  
                tree = move(tree->right);  
            }  
            else {  
                node* minNode = this->FindMin(tree->left);  
                tree->word = minNode->word;  
                tree->freq = minNode->freq;  
                this->Replace(minNode->word, s2, minNode);  
            }  
        }  
        else if(s1 < tree->word) {  
            this->Replace(s1, s2, tree->left);  
        }  
        else if(s1 > tree->word) {  
            this->Replace(s1, s2, tree->right);  
        }  
        else if(s1 == root->word) {  
            node* to_s2 = search(root, s2);  
            if(to_s2 == nullptr) {  
                this->insert(s2);  
                node* new_to_s2 = search(root, s2);  
                new_to_s2->freq += tree->freq-1;  
            }  
            else {  
                to_s2->freq += tree->freq;  
            }  
            if(root->left == nullptr && root->right == nullptr) {  
                root = nullptr;  
            }  
            else if(root->left != nullptr && root->right == nullptr) {  
                root = move(root->left);  
            }  
            else if(root->left == nullptr && root->right != nullptr) {  
                root = move(root->right);  
            }  
            else {  
                node* minNode = this->FindMin(root->left);  
                root->word = minNode->word;  
                this->Replace(minNode->word, s2, minNode);  
            }  
        }  
    }  
    node* FindMin(node* &tree) {  
        if(tree == nullptr) {  
            return 0;  
        }  
        else if(tree->right == nullptr) {  
            return tree;  
        }  
        else {  
            return this->FindMin(tree->right);  
        }  
    }  
  
    void inorder(node* tree) const{  
        if(tree == nullptr) {  
            return;  
        }  
        if(tree != nullptr) {  
            inorder(tree->left);  
            cout << tree->word << " " << tree->freq << endl;  
            inorder(tree->right);  
        }  
    }  
    lexicon() {  
        root = nullptr;  
    }  
    ~lexicon() {  
        node* t;  
        node* p = root->right;  
        for(t=root; t!=nullptr; t = t->left) {  
            node* temp = t;  
            delete temp;  
        }  
        for(t=p; t!=nullptr; t = t->right) {  
            node* temp = t;  
            delete temp;  
        }  
        delete p;  
    }  
  
    void insert(const string &s) {  
        if(root == nullptr) {  
            this->root = new node(s);  
        }  
        else {  
            this->Insert(s, this->root);  
        }  
    }  
    int lookup(const string &s) const {  
        return Look_up(s, this->root);  
    }  
    int depth(const string &s) const {  
        int deep=0;  
        return Depth(s, this->root, deep);  
    }  
    void replace(const string &s1, const string &s2) {  
        this->Replace(s1, s2, this->root);  
    }  
  
    friend ostream & operator << (ostream &out, const lexicon &l) {  
        l.inorder(l.root);  
        return out;  
    }  
};
Posted
Updated 31-May-21 20:34pm
v2
Comments
OriginalGriff 31-May-21 17:04pm
   
And?
Did you have a question?

Where are you stuck?
Whet help do you need?
gklempe27 31-May-21 17:06pm
   
my problem is in Replace method, the difference is on the output.
Greg Utas 31-May-21 17:59pm
   
You need to use a debugger. The larger a program gets, the harder it gets to debug it manually, whether by studying it or by using pencil and paper. I assume you're writing this program in a software course. In 3rd and 4th year university, I wrote programs that were 3,000 to 6,000 lines long. Imagine trying to find problems manually in programs that large. It rarely happens.

Compiling does not mean your code is right! :laugh:
Think of the development process as writing an email: compiling successfully means that you wrote the email in the right language - English, rather than German for example - not that the email contained the message you wanted to send.

So now you enter the second stage of development (in reality it's the fourth or fifth, but you'll come to the earlier stages later): Testing and Debugging.

Start by looking at what it does do, and how that differs from what you wanted. This is important, because it give you information as to why it's doing it. For example, if a program is intended to let the user enter a number and it doubles it and prints the answer, then if the input / output was like this:
Input   Expected output    Actual output
  1            2                 1
  2            4                 4
  3            6                 9
  4            8                16
Then it's fairly obvious that the problem is with the bit which doubles it - it's not adding itself to itself, or multiplying it by 2, it's multiplying it by itself and returning the square of the input.
So with that, you can look at the code and it's obvious that it's somewhere here:
C#
int Double(int value)
   {
   return value * value;
   }

Once you have an idea what might be going wrong, start using the debugger to find out why. Put a breakpoint on the first line of the method, and run your app. When it reaches the breakpoint, the debugger will stop, and hand control over to you. You can now run your code line-by-line (called "single stepping") and look at (or even change) variable contents as necessary (heck, you can even change the code and try again if you need to).
Think about what each line in the code should do before you execute it, and compare that to what it actually did when you use the "Step over" button to execute each line in turn. Did it do what you expect? If so, move on to the next line.
If not, why not? How does it differ?
Hopefully, that should help you locate which part of that code has a problem, and what the problem is.
This is a skill, and it's one which is well worth developing as it helps you in the real world as well as in development. And like all skills, it only improves by use!
   
Using the debugger shows you where your code needs some refurbishing.

some tips:
- seperate classes in extra files and working code into small functions
- sort your lexicon by self balanced tree theory
- make some debugging output in your functions to see what is going on (and delete when it isnt needed or gets too much)
- dont ferget to implement the time measurements

your homework is your task to improve your skills and learn coding. Take the chance to improve your skills and think about a career as well paid developer ;-)
   

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