C ++二进制搜索树比较节点数据并删除重复项

Question

I have created a binary search tree in c++ and have loaded it up with two types of data, strings and ints. I am reading a text file and loading the tree up alphabetically with the words I am pulling, and also the number of the line the word is found on. I am able to print the words and the numbers just fine. What I am wanting to do now is check to see if a word has already been printed, and if it has then I will only print out the number of the line from which the word is found on. The way I am thinking about doing this is by comparing previous data as the tree is traversed and printed. This is my print function.

void inOrderPrint(Node *rootPtr ) {
    if ( rootPtr != NULL ) {
        for (int i =0; rootPtr->data[i]; i++){
            while(ispunct(rootPtr->data[i]))
                rootPtr->data.erase(i,1);
                }
        rootPtr->data = rootPtr->data.substr(0,10);
        inOrderPrint( rootPtr->left );
        cout << (rootPtr->data)<<rootPtr->lineNum <<endl;
        inOrderPrint( rootPtr->right );
    }
}

This is what I was thinking:

if (rootPtr->data == previous rootPtr->data)
    cout<<setw(10)<<theCurrentNode lineNum;
else
    do normal printing

I think that if this function were to run on the first node and it compares it to the non existent previous node, it would automatically try to compare it to NULL, the if statement would return false and it would move on to the else.

Any suggestions on how to go about doing this with actual c++ syntax? Or does anyone see a flaw in my logic?

Thanks in advance!

Answer 1

This answer will describe how to make the program print unique entries and the line number of the first occurrence in the file. If there are duplicate occurrences it will print only the line number of the first occurrence for each duplicate occurrence. The approach is to make sure that there are no duplicate nodes in the tree and to count redundant occurrences.

To do this we might modify the node structure as follows:

struct Node{
    string data;
    int lineNum;
    int count =1;
    Node* left;
    Node* right;
};

The function Insert might be edited to count duplicates like this:

Node* Insert(Node* rootPtr,string data,int lineNum){
if(rootPtr == NULL){
    rootPtr = GetNewNode(data,lineNum);
    for (int i =0; rootPtr->data[i]; i++){
        while(ispunct(rootPtr->data[i]))
            rootPtr->data.erase(i,1);
            }
    rootPtr->data = rootPtr->data.substr(0,10);

    return rootPtr;
}
else if(data< rootPtr->data){
    rootPtr->left = Insert(rootPtr->left,data,lineNum);
    for (int i =0; rootPtr->data[i]; i++){
        while(ispunct(rootPtr->data[i]))
            rootPtr->data.erase(i,1);
            }
    rootPtr->data = rootPtr->data.substr(0,10);
}
else if(data > rootPtr->data) {
    rootPtr->right = Insert(rootPtr->right,data,lineNum);
    for (int i =0; rootPtr->data[i]; i++){
        while(ispunct(rootPtr->data[i]))
            rootPtr->data.erase(i,1);
            }
    rootPtr->data = rootPtr->data.substr(0,10);

}
else if(data == rootPtr->data)
    ++rootPtr->count;

return rootPtr;
}

Finally the print function can be modified:

void inOrderPrint(Node *rootPtr ) {
//ofstream outputFile;
//outputFile.open("Output.txt");

if ( rootPtr != NULL ) {
    inOrderPrint( rootPtr->left );
    cout << (rootPtr->data)<<" " << rootPtr->lineNum <<endl;
    int j =rootPtr->count;
    while( --j )
    cout << rootPtr->lineNum <<endl;

    //outputFile << (rootPtr->data)<<rootPtr->lineNum <<endl;
    inOrderPrint( rootPtr->right );
}
}

Now this should be much closer to what you want. It would also be a good idea to separate the text processing from the node processing. (This answer sort of assumes that you will take care of that.) Otherwise duplicate nodes will be created if the preprocessed text does not match the processed text.

Good luck!