基于C++實(shí)現(xiàn)的哈夫曼編碼解碼操作示例
本文實(shí)例講述了基于C++實(shí)現(xiàn)的哈夫曼編碼解碼操作。分享給大家供大家參考,具體如下:
哈夫曼編碼是一個(gè)通過哈夫曼樹進(jìn)行的一種編碼,一般情況下,以字符:‘0'與‘1'表示。編碼的實(shí)現(xiàn)過程很簡單,只要實(shí)現(xiàn)哈夫曼樹,通過遍歷哈夫曼樹,這里我們從每一個(gè)葉子結(jié)點(diǎn)開始向上遍歷,如果該結(jié)點(diǎn)為父節(jié)點(diǎn)的左孩子,則在字符串后面追加“0”,如果為其右孩子,則在字符串后追加“1”。結(jié)束條件為沒有父節(jié)點(diǎn)。然后將字符串倒過來存入結(jié)點(diǎn)中。
C++實(shí)現(xiàn)代碼如下:
#include<iostream> #include<string> using namespace std; struct Node { double weight; string ch; string code; int lchild, rchild, parent; }; void Select(Node huffTree[], int *a, int *b, int n)//找權(quán)值最小的兩個(gè)a和b { int i; double weight = 0; //找最小的數(shù) for (i = 0; i <n; i++) { if (huffTree[i].parent != -1) //判斷節(jié)點(diǎn)是否已經(jīng)選過 continue; else { if (weight == 0) { weight = huffTree[i].weight; *a = i; } else { if (huffTree[i].weight < weight) { weight = huffTree[i].weight; *a = i; } } } } weight = 0; //找第二小的數(shù) for (i = 0; i < n; i++) { if (huffTree[i].parent != -1 || (i == *a))//排除已選過的數(shù) continue; else { if (weight == 0) { weight = huffTree[i].weight; *b = i; } else { if (huffTree[i].weight < weight) { weight = huffTree[i].weight; *b = i; } } } } int temp; if (huffTree[*a].lchild < huffTree[*b].lchild) //小的數(shù)放左邊 { temp = *a; *a = *b; *b = temp; } } void Huff_Tree(Node huffTree[], int w[], string ch[], int n) { for (int i = 0; i < 2 * n - 1; i++) //初始過程 { huffTree[i].parent = -1; huffTree[i].lchild = -1; huffTree[i].rchild = -1; huffTree[i].code = ""; } for (int i = 0; i < n; i++) { huffTree[i].weight = w[i]; huffTree[i].ch = ch[i]; } for (int k = n; k < 2 * n - 1; k++) { int i1 = 0; int i2 = 0; Select(huffTree, &i1, &i2, k); //將i1,i2節(jié)點(diǎn)合成節(jié)點(diǎn)k huffTree[i1].parent = k; huffTree[i2].parent = k; huffTree[k].weight = huffTree[i1].weight + huffTree[i2].weight; huffTree[k].lchild = i1; huffTree[k].rchild = i2; } } void Huff_Code(Node huffTree[], int n) { int i, j, k; string s = ""; for (i = 0; i < n; i++) { s = ""; j = i; while (huffTree[j].parent != -1) //從葉子往上找到根節(jié)點(diǎn) { k = huffTree[j].parent; if (j == huffTree[k].lchild) //如果是根的左孩子,則記為0 { s = s + "0"; } else { s = s + "1"; } j = huffTree[j].parent; } cout << "字符 " << huffTree[i].ch << " 的編碼:"; for (int l = s.size() - 1; l >= 0; l--) { cout << s[l]; huffTree[i].code += s[l]; //保存編碼 } cout << endl; } } string Huff_Decode(Node huffTree[], int n,string s) { cout << "解碼后為:"; string temp = "",str="";//保存解碼后的字符串 for (int i = 0; i < s.size(); i++) { temp = temp + s[i]; for (int j = 0; j < n; j++) { if (temp == huffTree[j].code) { str=str+ huffTree[j].ch; temp = ""; break; } else if (i == s.size()-1&&j==n-1&&temp!="")//全部遍歷后沒有 { str= "解碼錯(cuò)誤!"; } } } return str; } int main() { //編碼過程 const int n=5; Node huffTree[2 * n]; string str[] = { "A", "B", "C", "D", "E"}; int w[] = { 30, 30, 5, 20, 15 }; Huff_Tree(huffTree, w, str, n); Huff_Code(huffTree, n); //解碼過程 string s; cout << "輸入編碼:"; cin >> s; cout << Huff_Decode(huffTree, n, s)<< endl;; system("pause"); return 0; }
運(yùn)行結(jié)果如下:
希望本文所述對大家C++程序設(shè)計(jì)有所幫助。
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