数据结构与算法综合实验(一)之二叉树与哈夫曼图片压缩

实验内容

1、创建工程。
2、读取源文件。
3、生成哈夫曼树。
4、生成哈夫曼编码。
5、压缩原文件。
6、保存压缩文件。
7、扩展功能。
实验代码参考：https://blog.csdn.net/cxh_1231/article/details/80530668
main.cpp
主函数

#include "iostream"
#include "file.h"
#include"HuffmanTree.h"
using namespace std;
int main() {
	cout << "请输入文件名:";
	char filename[256];
	cin >> filename;
	if (Compress(filename) == 1) {
		cout << "\n压缩完成！" << endl;
	}
	else cout << "\n压缩失败！" << endl;
	return 0;
}

HuffmanTree.h
哈夫曼树头文件

#ifndef HuffmanTree_H
#define HuffmanTree_H
#include
typedef struct HuffmanTree
{
	int weight;
	int id;
	struct HuffmanTree* lchild;
	struct HuffmanTree* rchild;
	int num[50];
}HuffmanNode;
HuffmanNode* createHuffmanTree(int* a, int n);
void HuffmanCode(HuffmanNode* hufmTree, int depth,long long &sum);
void PHuffmanCode(HuffmanNode* hufmTree, int depth, int id, char *p);
#endif 

HuffmanTree.cpp
哈夫曼树源文件

#include"HuffmanTree.h"
#include"stdio.h"
#include"stdlib.h"
HuffmanNode* createHuffmanTree(int* a, int n)
{
	int i, j;
	HuffmanNode **temp, *hufmTree = NULL;
	temp = (HuffmanNode**)malloc(n * sizeof(HuffmanNode));
	for (i = 0; i < n; ++i) {
		temp[i] = (HuffmanNode*)malloc(sizeof(HuffmanNode));
		temp[i]->weight = a[i];
		temp[i]->id = i;
		temp[i]->lchild = temp[i]->rchild = NULL;
	}
	for (i = 0; i < n - 1; ++i) {
		int small1 = -1, small2;
		for (j = 0; j < n; ++j) {
			if (temp[j] != NULL && small1 == -1) {
				small1 = j;
				continue;
			}
			else if (temp[j] != NULL) {
				small2 = j;
				break;
			}
		}
		for (j = small2; j < n; ++j) {
			if (temp[j] != NULL) {
				if (temp[j]->weight < temp[small1]->weight) {
					small2 = small1;
					small1 = j;
				}
				else if (temp[j]->weight < temp[small2]->weight) {
					small2 = j;
				}
			}
		}
		hufmTree = (HuffmanNode*)malloc(sizeof(HuffmanNode));
		hufmTree->weight = temp[small1]->weight + temp[small2]->weight;
		hufmTree->lchild = temp[small1];
		hufmTree->rchild = temp[small2];
		temp[small1] = hufmTree;
		temp[small2] = NULL;
	}
	free(temp);
	return hufmTree;
}
void HuffmanCode(HuffmanNode* hufmTree, int depth,long long  &sum) {
	static int code[20];
	if (hufmTree) {
		if (hufmTree->lchild == NULL && hufmTree->rchild == NULL) {
			printf("id为%d权值为%d的叶子结点的哈夫曼编码为 ", hufmTree->id, hufmTree->weight);
			int i;
			sum += depth * hufmTree->weight;
			for (i = 0; i < depth; ++i) {
				printf("%d", code[i]);
			}
			printf("\n");
		}
		else {
			code[depth] = 0;
			HuffmanCode(hufmTree->lchild, depth + 1, sum);
			code[depth] = 1;
			HuffmanCode(hufmTree->rchild, depth + 1, sum);
		}
	}
}
void PHuffmanCode(HuffmanNode* hufmTree, int depth,int id,char *p) {
	static int code[20];
	if (hufmTree) {
		if (hufmTree->id==id) {
			int i;
			for (i = 0; i < depth; ++i) {
				p[i] = code[i];
			}
			return;
		}
		else {
			code[depth] = 0;
			PHuffmanCode(hufmTree->lchild, depth + 1, id,p);
			code[depth] = 1;
			PHuffmanCode(hufmTree->rchild, depth + 1, id,p);
		}
	}
}

file.h
文件头文件

#ifndef File_H
#define File_H
int Compress(const char *pFilename);
char Str2byte(const char *p);
#endif

file.cpp
文件源文件

#define _CRT_SECURE_NO_WARNINGS//消除scanf警告
#include"file.h"
#include"HuffmanTree.h"
#include"stdlib.h"
#include"iostream"
using namespace std;
int Compress(const char *pFilename) {
	int weight[256] = { 0 };
	FILE *in = fopen(pFilename, "rb");
	int temp;
	long long length=0;
	while ((temp = getc(in)) != EOF) {
		weight[temp]++;
		length++;
	}
	fclose(in);
	cout << "显示256种字节出现的次数：" << endl;
	cout << "Byte\t" << "Weight" << endl;
	for (int i = 0; i < 256; i++) {
		printf("0x%02X\t%d\n", i, weight[i]);
	}
	long long sum = 0;
	HuffmanTree *HT=createHuffmanTree(weight, 256);
	HuffmanCode(HT, 0, sum);
	int left = sum % 8;
	sum = left ? sum / 8 + 1 : sum;
	char *Buffer = (char*)malloc(sizeof(char)*sum);
	char filename[256] = { 0 };
	strcpy(filename, pFilename);
	strcat(filename, ".temp");
	FILE *out = fopen(filename, "wb");
	FILE *in2 = fopen(pFilename, "rb");
	int pos = 0;
	char ch[50] = { 0 };
	char cd[256] = { 0 };
	for (int i = 0; i < length; i++) {
		temp = getc(in);
		PHuffmanCode(HT, 0, temp, ch);
		strcat(cd, ch);
		while (strlen(cd) >= 8) {
			Buffer[pos++] = Str2byte(cd);
			for (int i = 0; i < 248; i++) cd[i] = cd[i + 8];
		}
	}
	if (strlen(cd) > 0) {
		Buffer[pos++] = Str2byte(cd);
	}
	for (int i = 0; i < strlen(Buffer); i++) {
		fputc(Buffer[i], out);
	}
	fclose(in2);
	fclose(out);
	
	cout << "目标文件大小：" << length << "字节" << endl;
	cout << "压缩文件大小：" << sum << "字节" << endl;
	cout << "压缩比率：" << (double)sum * 100 / length << "%" << endl;
	system("pause");
	return 1;
}
char Str2byte(const char *p) {
	char b = 0x00;
	for (int i = 0; i < 8; i++) {
		b = b << 1;
		if (p[i] == '1') {
			b = b | 0x01;
		}
	}
	return b;
}