页面置换算法（FIFO，LRU，最佳，Clock)

#include<iostream>
using namespace std;
void Print(int bc[],int blockCount)
{
for(int i=0;i<blockCount;i++)
{
cout<<bc[i]<<" ";
}
cout<<endl;
}

bool Travel(int bc[],int blockCount,int x)
{
bool is_found=false;
int i;
for(i=0;i<blockCount;i++)
{
if(bc[i]==x)
{
is_found=true;
break;
}
}
return is_found;
}

void FIFO(int pc[],int bc[],int pageCount,int blockCount)
{
cout<<"0：FIFO置换算法"<<endl;
int i;
if(pageCount<=blockCount)
{
cout<<"缺页次数为"<<0<<endl;
cout<<"缺页率为"<<0<<endl;
}
else
{
int noPage=0;
int p=0;
for(i=0;i<pageCount;i++)
{

cout<<"引用页："<<pc[i]<<endl;
if(!Travel(bc,blockCount,pc[i]))
{
if(i<blockCount)
{
bc[i]=pc[i];
}
else
{
if(p==blockCount)
{
p=0;
}
bc[p]=pc[i];
p++;

}
noPage++;
cout<<"物理快情况：";
Print(bc,blockCount);
}
cout<<endl;
}
cout<<"缺页次数为:"<<noPage<<endl;
cout<<"缺页率为:"<<(float)noPage/pageCount<<endl;
}
}

int FoundMaxNum(int a[],int n)
{
int k,j;
k=a[0];
j=0;
for (int i=0;i<n;i++)
{
if(a[i]>=k)
{
k=a[i];
j=i;
}
}
return j;
}

void LRU(int pc[],int bc[],int pageCount,int blockCount)
{
cout<<"1：LRU置换算法"<<endl;
if(pageCount<=blockCount)
{
cout<<"缺页次数为"<<0<<endl;
cout<<"缺页率为"<<0<<endl;
}
else
{
int noPage=0;
int i,j,m;
int *bc1=new int[blockCount];
for(i=0;i<blockCount;i++)
{
bc1[i]=0;
}
for(i=0;i<pageCount;i++)
{
cout<<"引用页："<<pc[i]<<endl;
if(!Travel(bc,blockCount,pc[i]))
{
if(i<blockCount)
{
bc[i]=pc[i];
for(int p=0;p<=i;p++)
{
bc1[p]++;
}
}
else
{
for(j=0;j<blockCount;j++)
{
bc1[j]++;
}
int k=FoundMaxNum(bc1,blockCount);
bc[k]=pc[i];
bc1[k]=1;

}
noPage++;
cout<<"物理快情况：";
Print(bc,blockCount);
}
else if(Travel(bc,blockCount,pc[i]))
{
if(i<blockCount)
{
for(j=0;j<=i;j++)
{
bc1[j]++;
}
for(m=0;m<=i;m++)
{
if(bc[m]==pc[i])
{
break;
}
}
bc1[m]=1;
bc[m]=pc[i];

}
else
{
for(j=0;j<blockCount;j++)
{
bc1[j]++;
}
for(m=0;m<blockCount;m++)
{
if(bc[m]==pc[i])
{
break;
}
}
bc1[m]=1;
bc[m]=pc[i];
}
}
cout<<endl;
}
cout<<"缺页次数为:"<<noPage<<endl;
cout<<"缺页率为:"<<(float)noPage/pageCount<<endl;
delete bc1;
}
}

void Optiomal(int pc[],int bc[],int pageCount,int blockCount)
{
cout<<"2：最佳置换算法"<<endl;
if(pageCount<=blockCount)
{
cout<<"缺页次数为"<<0<<endl;
cout<<"缺页率为"<<0<<endl;
}
else
{
int noPage=0;
int i,j,k;
for(i=0;i<pageCount;i++)
{
cout<<"引用页："<<pc[i]<<endl;
if(!Travel(bc,blockCount,pc[i]))
{
if(i<blockCount)
{
bc[i]=pc[i];
}
else
{
int max=0;
int blockIndex;;
for(j=0;j<blockCount;j++)
{
for(k=i;k<pageCount;k++)
{
if(bc[j]==pc[k])
{
break;
}
}
if(k>=max)
{
max=k;
blockIndex=j;
}
}
bc[blockIndex]=pc[i];

}
noPage++;
cout<<"物理快情况：";
Print(bc,blockCount);
}
cout<<endl;
}
cout<<"缺页次数为:"<<noPage<<endl;
cout<<"缺页率为:"<<(float)noPage/pageCount<<endl;
}
}

void NRU(int pc[],int bc[],int pageCount,int blockCount)
{
cout<<"3：Clock置换算法"<<endl;
if(pageCount<=blockCount)
{
cout<<"缺页次数为"<<0<<endl;
cout<<"缺页率为"<<0<<endl;
}
else
{
int noPage=0;
int i,j;
int *bc1=new int[blockCount];
for(i=0;i<blockCount;i++)
{
bc1[i]=0;
}
for(i=0;i<pageCount;i++)
{
cout<<"引用页："<<pc[i]<<endl;
if(!Travel(bc,blockCount,pc[i]))
{
for(j=0;j<blockCount;j++)
{
if(bc1[j]==1)
{
bc1[j]=0;
}
else if(bc1[j]==0)
{
break;
}
if(j==blockCount-1)
{
j=-1;
}
}
bc[j]=pc[i];
bc1[j]=1;
noPage++;
cout<<"物理快情况：";
Print(bc,blockCount);
}
cout<<endl;
}
cout<<"缺页次数为:"<<noPage<<endl;
cout<<"缺页率为:"<<(float)noPage/pageCount<<endl;
delete bc1;
}
}
int main()
{
int pageCount,blockCount,i;
cout<<"输入页面数"<<endl;
cin>>pageCount;
int *pc=new int[pageCount];
cout<<"输入页面走向"<<endl;
for(i=0;i<pageCount;i++)
{
cin>>pc[i];
}
cout<<"输入物理块数"<<endl;
cin>>blockCount;
cout<<"0：FIFO置换算法"<<endl;
cout<<"1：LRU置换算法"<<endl;
cout<<"2：最佳置换算法"<<endl;
cout<<"3：Clock置换算法"<<endl;
cout<<"按数字选择算法类别："<<endl;
int n;
while(cin>>n)
{
if(n==0)
{
int *bc=new int[blockCount];
FIFO(pc,bc,pageCount,blockCount);
delete bc;
}
else if(n==1)
{
int *bc=new int[blockCount];
LRU(pc,bc,pageCount,blockCount);
delete bc;
}
else if(n==2)
{
int *bc=new int[blockCount];
Optiomal(pc,bc,pageCount,blockCount);
delete bc;
}
else if(n==3)
{
int *bc=new int[blockCount];
for(i=0;i<blockCount;i++)
{
bc[i]=-1;
}
NRU(pc,bc,pageCount,blockCount);
delete bc;
}
else break;
}
delete pc;
return 0;
}