fei nuo.txt

信息论与编码 费诺编码源程序信息论与编码

#include<iostream.h>
#include<math.h>
#include<iomanip.h>
#include<stdlib.h>
class T
{
public:
 T() {}
 ~T();
 void Create();
 void Coutpxj();
 void Coutk();
 void Coutz();
 void Print();
protected:
 int n;
 double *p;
 double *pxj;
 int *k;
    double *mz;
};

void T::Create()
{
 cout<<"请输入信源符号个数:";
    cin>>n;
    p=new double[n];
    cout<<"请分别输入这"<<n<<"个概率:\n";
    for(int i=0;i<n;i++)
        cin>>p[i];
    pxj=new double[n];
    k=new int[n];
    mz=new double[n];
 double sum=0.0;
 for(i=0;i<n;i++)
     sum+=p[i];
 if(sum!=1.0)
  throw 1;
    else
 {
  for(i=0;i<n;i++)
  {
            int k=i;
            for(int j=i+1;j<n;j++)
      if(p[k]<p[j]) k=j;
         double m=p[i];
         p[i]=p[k];
         p[k]=m;
  }
 }
}

T::~T()
{
    delete p;
    delete pxj;
    delete k;
    delete mz;
}

void T::Coutpxj()
{
    pxj[0]=0;
    for(int i=1;i<n;i++)
 {
        pxj[i]=0;
     for(int j=0;j<i;j++)
      pxj[i]+=p[j];
 }
}

void T::Coutk()
{
 for(int i=0;i<n;i++)
 {
     double d=(-1)*(log(p[i])/log(2));
  if(d-(int)d>0)    k[i]=(int)d+1;
        else    k[i]=(int)d;
 }
}

void T::Print()
{
 cout<<"Xi"<<setw(8)<<"P(xi)"
        <<setw(8)<<"Pa(xj)"
     <<setw(8)<<"Ki"
     <<setw(8)<<"码字"
     <<endl;
    for(int i=0;i<n;i++)
    {    cout<<"X"<<i+1
       <<setw(8)<<setprecision(2)<<p[i]
    <<setw(8)<<setprecision(2)<<pxj[i]
    <<setw(8)<<k[i]<<"    ";
         mz[i]=pxj[i];
   for(int j=0;j<k[i];j++)
   {
       if(2*mz[i]-1>=0)    
    {
     cout<<1;
     mz[i]=2*mz[i]-1;
    }
    else    
    {
     cout<<0;
     mz[i]=2*mz[i];
    } 
   }
   cout<<endl;
 }
 double K=0.0,H=0.0,Y;
 for(i=0;i<n;i++)
 {
  K+=(double)p[i]*k[i];
  H+=(-1)*p[i]*(log10(p[i])/log10(2.0));
 }
  Y=H/K;
  cout<<"平均码长:"<<K<<endl;
  cout<<"信源熵:"<<H<<endl;
  cout<<"编码效率:"<<Y<<endl;

}

void main()
{
    T t;int e;
 try
 {
     t.Create();
        t.Coutpxj();
        t.Coutk();
        t.Print();
 }
 catch(int e) 
 {if(e==1) cout<<"输入错误，请重新运行";}
}