C++实现哈夫曼树编码解码

代码：

#pragma once
#include<iostream>
#include<stack>
using  namespace std;
#define m 20
stack<int> s;
/*哈夫曼树结点类HuffmanNode声明*/
template<class T>
class HuffmanNode {
private:
	HuffmanNode<T> * left;
	HuffmanNode<T> * right;
	T data;
	int weight;
public:
	HuffmanNode(){}
	HuffmanNode(const T& item, HuffmanNode<T> * l, HuffmanNode<T> * r):data(item),left(l),right(r){}
	HuffmanNode<T> * getLeft() { return left; }
	void setLeft(HuffmanNode<T> * left) { this->left = left; }
	HuffmanNode<T> * getRight() { return right; }
	void setRight(HuffmanNode<T> * right) { this->right=right; }
	T& getData() { return data; }
	void setData(const T& item) { data = item; }
	int getWeight() { return weight; }
	void setWeight(int weight) { this->weight = weight; }
};

/*哈夫曼树类HuffmanTree声明*/
template<class T>
class HuffmanTree {
private:
	HuffmanNode<T> * root;
	T data[m];
	int weight[m];
	int count;
public:
	HuffmanTree(HuffmanNode<T> * t=NULL):root(t){}
	void CreateHuffmanTree();//创建哈夫曼树
	HuffmanNode<T> * getRoot() { return root; }
	void setRoot(HuffmanNode<T> * t) { root = t; }
	void inputNodes();//输入各个结点的data和weight值
	HuffmanNode<T> * deCode(HuffmanNode<T>*t,T item);
	void showCode();
};

template<class T>
inline void HuffmanTree<T>::CreateHuffmanTree()
{
	inputNodes();
	HuffmanNode<T> ** H = new HuffmanNode<T>*[count];
	HuffmanNode<T> * p1 = NULL, *p2 = NULL, * p,* t;
	for (int i = 0; i < count; i++) {
		H[i] = new HuffmanNode<T>();
		H[i]->setData(data[i]);
		H[i]->setWeight(weight[i]);
		H[i]->setLeft(NULL);
		H[i]->setRight(NULL);
	}

	for (int i = 0; i < count - 1; i++) {
		p = new HuffmanNode<T>();
		p1 = H[i];
		p2 = H[i + 1];
		p->setLeft(p1);
		p->setRight(p2);
		p->setWeight(p1->getWeight() + p2->getWeight());
		//将新的结点插入结点数组中的合适位置,并将被合并的两个结点删除
		t = p;
		int j = i + 2;
		while ( j < count &&H[j]->getWeight() < t->getWeight()) {
			H[j - 1] = H[j];
			j++;
		}
		H[j - 1] = t;
	}
	root = H[count - 1];
}

template<class T>
inline void HuffmanTree<T>::inputNodes()
{
	int i = 0;
	for (int j = 0; j < m; j++) {
		data[j] = NULL;
		weight[j] = 0;
	}
	while (cin >> data[i] >> weight[i]) {
		i++;
	}
	count = i;
}

template<class T>
inline HuffmanNode<T>* HuffmanTree<T>::deCode( HuffmanNode<T> * t,T item)
{
	HuffmanNode<T> * p, * q;
	if(t==NULL)
		return NULL;
	if (t->getData() == item)
		return t;
	if ((p = deCode(t->getLeft(), item))!=NULL) {
		s.push(0);
		return p;
	}
	else if((q = deCode(t->getRight(), item))!=NULL){
		s.push(1);
		return q ;
	}
}

template<class T>
inline void HuffmanTree<T>::showCode()
{
	cout << root->getWeight() << endl;
	cout << (root->getLeft())->getRight()->getData() << endl;
	for (int i = 0; i < count; i++) {
		cout << data[i] << "——";
		deCode(root, data[i]);
		while (!s.empty()) {
			cout << s.top();
			s.pop();
		}
		cout << endl;
	}
}

测试程序：

#include<iostream>
#include"HuffmanTree.h"
using namespace std;

int main() {
	HuffmanTree<char> * tree = new HuffmanTree<char>();
	tree->CreateHuffmanTree();
	tree->showCode();
	system("pause");
	return 0;
}

测试数据：
n 1
s 3
t 4
a 10
i 12
p 13
e 15
Ctrl+Z 回车结束输入
输入时权值由小到大排序…也可以在程序里加一个排序

结果：