信息论相关编程C\C++实现

#include <iostream.h> #include <cmath> #define M 20 //定义符号序列的最大长度 #define N 2 //定义信源符号个数 class CalCode { public: int length; //定义符号序列的实际长度 char n, sample[N]; //存放信源符号 double c, chance[N]; //存放信源符号的对应概率 char code[M]; //存放符号序列 double High, Low, high, low, data; //定义用于计算的各个变量 CalCode() //变量赋初值 { High = 0; Low = 0; } void Get_value(); //此函数用于提示输入信源相关值 void Get_code(); //此函数用于提示输入符号序列相关值 void coding(); //此函数用于具体的算术编码和结果输出 ~CalCode(){} //析构函数,做清理工作 }; void CalCode::Get_value() //此函数用于提示输入信源相关值 { int i; cout << "请输入" << N << "个信源符号:" << endl; for(i = 0; i < N; i++) { cin >> n; sample[i] = n; } cout << endl << "请输入" << N << "个信源符号对应的概率:" << endl; for(i = 0; i < N; i++) { cin >> c; chance[i] = c; } } void CalCode::Get_code() //此函数用于提示输入符号序列相关值 { int i; cout << endl << "请输入符号序列长: "; cin >> length; //判断输入的符号序列长度是否大于预定的值 while(length >= M) { cout << endl << "您输入的符号序列过长,请改小: "; cin >> length; } cout << endl << "请输入要编码的符号序列: "; for(i = 0; i < length; i++) cin >> code[i]; } void CalCode::coding() //此函数用于具体的算术编码和结果输出 { int i, k, l, c, j = 0, calcode[M]; double b, chance_l, Ps = 1; for(i = 0; i < N; i++) if(code[0] == sample[i]) break; while(j < i) Low += chance[j++]; data = chance[j]; High = Low + data; for(i = 1; i < length; i++) for(j = 0; j < N; j++) { if(code[i] == sample[j]) { if(j == 0) { low = Low; high = Low + chance[j] * data; High = high; data *= chance[j]; } else { chance_l = 0.0; for(k = 0; k <= j - 1; k++) chance_l += chance[k]; low = Low + data * chance_l; high = Low + data * (chance_l + chance[j]); Low = low; High = high; data *= chance[j]; } } else continue; } //输出F(s)的计算结果 cout << endl << "经计算得到符号序列 "; for(i = 0; i < length; i++) cout << code[i]; cout << " 的F(s)为: " << Low << endl << endl; //计算算术编码的码字长度l for(i = 0; i < N; i++) for(j = 0; j < length; j++) if(sample[i] == code[j]) Ps *= chance[i]; l = int( ( log( 1.0 / Ps ) / log(2) ) + 0.999999 ); cout << "经计算得到算术编码的码字长度为: " << l << endl ; //将F(s)转换为二进制,并存放于数组calcode中 for(i = 0; i < l; i++) { b = Low * 2; c = int(b); Low = b - c; calcode[i] = c; } //解决有关算术编码的进位问题,给二进制数加1 if(calcode[l - 1] == 1) { for(i = l - 2; i >= 0;) { if(calcode[i] == 0) { calcode[i] = 1; break; } else { calcode[i] = 0; i--; } } calcode[l - 1] = 0; } else calcode[l - 1] = 1; //输出算术编码的结果 cout << endl << "将F(s)转换为算术编码的最终结果为: "; for(i = 0; i < l; i++) cout << calcode[i]; cout << endl << endl; } //主函数 int main() { CalCode a; //各个函数的调用 a.Get_value(); a.Get_code(); a.coding(); return 0; }