浙江理工大学操作系统实验三页面置换算法

1、操作系统实验报告班级：计算机科学与技术三班 姓名：李生启 学号：2013329620077实验三：页面置换算法一、 实验目的1、熟悉内存分页管理策略。 2、编写OPT、FIFO、LRU，LFU四种置换算法并模拟实现。3、锻炼知识的运用能力和实践能力。二、 实验内容设计主界面，输入一串系列模拟页面请求，实现以下算法： 1) 最佳置换算法(OPT)：将以后永不使用的或许是在最长(未来)时间内不再 被访问的页面换出。 2) 先进先出算法(FIFO)：淘汰最先进入内存的页面，即选择在内存中驻留 时间最久的页面予以淘汰。 3) 最近最久未使用算法(LRU)：淘汰最近最久未被使用的页面。 4) 最不经常使

2、用算法(LFU)三、 代码及运行结果分析1.代码：（采用C+，环境：VS2010）#include<iostream>#include<string>#include <fstream>#include<stdio.h>using namespace std;void OPT(int count)int all50;int bracket3;int bll50=0;ifstream fin("abc.txt");if( fin.is_open() ) for(int i=0;i<count;i+)fin>>a

3、lli;fin.close();bracket0=all0;bracket1=all1;bracket2=all2;for(int i=0;i<count;i+)if(i<3) if(i=0) cout<<"当前序列："<<endl;cout<<bracket0<<endl; if(i=1) cout<<"当前序列："<<endl;cout<<bracket0<<" "<<bracket1<<endl;

4、if(i=2) cout<<"当前序列："<<endl;cout<<bracket0<<" "<<bracket1<<" "<<bracket2<<endl; if(i>=3)int a_num=count+1;int b_num=count+1;int c_num=count+1;int qi=0;for(int x=0;x<3;x+)if(bracketx=alli)cout<<"当前序列："

5、<<endl;cout<<bracket0<<" "<<bracket1<<" "<<bracket2<<endl;qi=6; break;if(qi=0)for(int e=i+1;e<count;e+)if(bracket0=alle)a_num=e;break;for(int e=i+1;e<count;e+)if(bracket1=alle)b_num=e;break;for(int e=i+1;e<count;e+)if(bracket2=al

6、le)c_num=e;break;if(a_num>=b_num)&&(a_num>=c_num)bracket0=alli;else if(b_num>=a_num)&&(b_num>=c_num)bracket1=alli;else if(c_num>=b_num)&&(c_num>=a_num)bracket2=alli;cout<<"当前序列："<<endl;cout<<bracket0<<" "<<br

7、acket1<<" "<<bracket2<<endl;void FIFO(int count)int bll50=0;int all50;int top=0;ifstream fin("abc.txt");if( fin.is_open() ) for(int i=0;i<count;i+)fin>>alli;fin.close();for(int i=0;i<count;i+)if(top<3)blltop=alli; top+; if(top=1) cout<<"

8、;当前序列："<<endl;cout<<blltop-1<<endl; if(top=2) cout<<"当前序列："<<endl;cout<<blltop-1<<" "<<blltop-2<<endl; if(top=3) cout<<"当前序列："<<endl;cout<<blltop-1<<" "<<blltop-2<<&

9、quot; "<<blltop-3<<endl; if(top>=3)if(alli!=blltop-1)&&(alli!=blltop-2)&&(alli!=blltop-3)blltop=alli;top+;cout<<"当前序列："<<endl;cout<<blltop-1<<" "<<blltop-2<<" "<<blltop-3<<endl;void LRU(

10、int count)int bll50=0;int all50;int top=0;ifstream fin("abc.txt");if( fin.is_open() ) for(int i=0;i<count;i+)fin>>alli;fin.close();for(int i=0;i<count;i+)if(top<3)blltop=alli; top+; if(top=1) cout<<"当前序列："<<endl;cout<<blltop-1<<endl; if(top=

11、2) cout<<"当前序列："<<endl;cout<<blltop-1<<" "<<blltop-2<<endl; if(top=3) cout<<"当前序列："<<endl;cout<<blltop-1<<" "<<blltop-2<<" "<<blltop-3<<endl; if(top>=3)int end3;in

12、t point=0;blltop=alli;top+;end0=blltop-1;point+;for(int i=top-2;i>=0;i-)if(point=3)cout<<"当前序列："<<endl; cout<<end0<<" "<<end1<<" "<<end2<<endl;point=0;break; else if(point=1)&&(end0!=blli)endpoint=blli;point+;el

13、se if(point=2)&&(end0!=blli)&&(end1!=blli)endpoint=blli;point+;void LFU(int count)int all50;int bll50=0;int top=0;int bracket3;ifstream fin("abc.txt");if( fin.is_open() ) for(int i=0;i<count;i+)fin>>alli;fin.close(); bracket0=all0;bracket1=all1;bracket2=all2;for(in

14、t i=0;i<count;i+)int a_num=0;int b_num=0;int c_num=0;int qi=0;if(i<3) if(i=0) cout<<"当前序列："<<endl;cout<<bracket0<<endl; if(i=1) cout<<"当前序列："<<endl;cout<<bracket0<<" "<<bracket1<<endl; if(i=2) cout<<

15、;"当前序列："<<endl;cout<<bracket0<<" "<<bracket1<<" "<<bracket2<<endl; if(i>=3)for(int x=0;x<3;x+)if(bracketx=alli)cout<<"当前序列："<<endl;cout<<bracket0<<" "<<bracket1<<&quo

16、t; "<<bracket2<<endl;qi=6; break;if(qi=0)for(int e=0;e<=i;e+)if(bracket0=alle)a_num+;for(int e=0;e<=i;e+)if(bracket1=alle)b_num+;for(int e=0;e<=i;e+)if(bracket2=alle)c_num+;if(a_num<=b_num)&&(a_num<=c_num)bracket0=alli;else if(b_num<=a_num)&&(b_num&

17、lt;=c_num)bracket1=alli;else if(c_num<=b_num)&&(c_num<=a_num)bracket2=alli;cout<<"当前序列："<<endl;cout<<bracket0<<" "<<bracket1<<" "<<bracket2<<endl;int main()int a50;int count=0;cout<<"请输入页面请求序列的个数：&

18、quot;<<endl;cin>>count;ofstream out("abc.txt");cout<<"请输入页面请求序列："<<endl;if(out.is_open()for(int i=0;i<count;i+) cin>>ai; out << ai<< endl; out.close( );while(true)int choose;cout<<"-"<<endl; cout<<"最佳置换

19、算法(OPT)-1"<<endl; cout<<"先进先出算法(FIFO)-2"<<endl; cout<<"最近最久未使用算法(LRU)-3"<<endl; cout<<"最不经常使用算法(LFU)-4"<<endl; cout<<"退出系统-5"<<endl; cout<<"-"<<endl; cout<<"输入要执行的操作；"<<endl; cin>>choose; switch(choose) case 1:OPT(count);break; case 2