How to make an array of pointer. What did i did wrong in the function below. I t

Question

How to make an array of pointer. What did i did wrong in the function below. I tried to write codes based on the conditions shown in the comments but its not working. Can some one help me with that?

/*
Creates an array of HuffmanNodes (more specifically, pointers to HuffmanNodes)
based on the given character-frequency pairs.

characters: an array of char
frequencies: an array of int
length: the length of characters and frequencies arrays

returns: an array of HuffmanNode*

Note: For 0 <= i < length, the frequency of the character characters[i]
is found at frequencies[i].
*/
HuffmanNode **genHuffmanNodes(char *characters, int *frequencies, int length)
{
// TODO
cout << "genHuffmanNodes activated! " << endl;
HuffmanNode **arr;

//arr = new (HuffmanNode*[length]);
//HuffmanNode *arr;

for (int i = 0;i < length; i++)
{
arr[i]->character = characters[i];
arr[i]->frequency = frequencies[i];
}

for (int i=0; i<length;i++)
{
cout << "starting of the loop: " << endl;
cout << "i is: " << i << endl;
cout << "character[i] is :" << arr[i]->character << endl;
cout << "frequency[i] is :" << arr[i]->frequency << endl;
}

return arr;
}

Explanation / Answer

Program:

#include<iostream>

#include<fstream>

#include<deque>

#include<algorithm>

#include<vector>

#include<string>

#include<queue>

using namespace std;

struct Node

{

double frequency;

char alphabet;

Node *left;

Node *right;

Node::Node()

{

frequency = 0;

alphabet = ' ';

left = NULL;

right = NULL;

}

};

struct Code{

char alp;

string code;

};

vector<Code> allCodes;

void BuildHuffmanTree();

void getCode(Node *root, string soFar);

void printTree(Node *root);

int main()

{

string plainText;

string codedText = "";

cout << "Please enter the text you would like to convert: " << endl;

cin >> plainText;

BuildHuffmanTree();

for(int i = 0; i < plainText.size(); i++)

{

char temp;

string tempA;

temp = plainText[i];

for(int j = 0; j < allCodes.size(); j++)

{

if(allCodes[j].alp == temp)

codedText.append(allCodes[j].code);

}

}

cout << codedText << endl;

return 0;

}

void BuildHuffmanTree()

{

ifstream input;

input.open("FrequencyTable1.txt");

ofstream output;

output.open("HuffmanCode.txt");

deque<Node> frequencyVector;

Node *Root;

double check = 0.000;

Node test;

vector<char> alphabets;

//Storing the frequency into a deque.

for(int k = 0; k < 26; k++)

{

Node temp;

char tempChar;

double tempFrequency;

input >> tempChar;

input >> tempFrequency;

temp.alphabet = tempChar;

temp.frequency = tempFrequency/100;

check+= tempFrequency;

temp.left = NULL;

temp.right = NULL;

alphabets.push_back(tempChar);

frequencyVector.push_back(temp);

}

sort(frequencyVector.begin(), frequencyVector.end());

//cout << check << endl;

for(int i = 0; i < frequencyVector.size(); i++)

{

cout << frequencyVector[i].frequency << " ";

}

cout << endl;

//Creating the Huffman Tree.

while(frequencyVector.size() >= 2)

{

Node tempOne;

Node tempTwo;

Node anotherTemp;

double tempFrequency = 0;

double tempChar;

anotherTemp.left = &frequencyVector.front();

tempFrequency += frequencyVector.front().frequency;

frequencyVector.pop_front();

anotherTemp.right = &frequencyVector.front();

tempFrequency += frequencyVector.front().frequency;

frequencyVector.pop_front();

anotherTemp.frequency = tempFrequency;

frequencyVector.push_back(anotherTemp);

sort(frequencyVector.begin(), frequencyVector.end());

cout << endl;

}

//Getting the Huffman code for each alphabet.

Root = &frequencyVector.front();

getCode(Root, "");

//printTree(&Root);

for(int i = 0; i < allCodes.size(); i++)

{

cout << allCodes[i].alp << " :" << allCodes[i].code << endl;

output << allCodes[i].alp << " :" << allCodes[i].code << endl;

}

}

bool operator < (const Node &one, const Node &two)

{

if(one.frequency < two.frequency)

return 1;

else

return 0;

}

void getCode(Node *root, string soFar)

{

if(root == NULL)

return;

if(!(root->left) && !(root->right))

{

Code temp;

temp.alp = root->alphabet;

temp.code = soFar;

allCodes.push_back(temp);

}

else

{

//Add a 0 if we go left.

getCode(root->left,(soFar.append("0")));

soFar.erase(soFar.size()-1);

//Add a 1 if we go right.

getCode(root->right,(soFar.append("1")));

}

}

void printTree(Node *root)

{

if (!root) return;

printTree(root->left);

cout << root->alphabet<< " ";

printTree(root->right);

}

Related Questions

Navigate

• Browse (All)
• Browse H
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.