FCFS和SJF调度算法1

1、以下参考的别人的：FCFS和SJF调度算法思想和实现算法算法思想：设计程序模拟进程的先来先服务FCFS和短作业优先SJF调度过程。假设有n个进程分别在Ti,，Tn时刻到达系统，它们需要的服务时间分别为Si,，Sn。分别采用先来先服务FCFS和短作业优先SJF进程调度算法进行调度，计算每个进程的完成时间，周转时间和带权周转时间，并且统计n个进程的平均周转时间和平均带权周转时间。源程序：#include<iomanip.h>#include<iostream.h>staticconstintN=100;intarrivalTimeN;/到达时间intserviceTimeN

2、;/服务时间intfinishTimeN;/完成时间intWholeTimeN;/周转时间doubleWeightWholeTimeN;/带权周转时间doubleaverageWT,averageWWT;/平均周转时间intserviceTime_SJFN;intn=0;intnowTime=0;/记录当前时间inti;voidFCFS()(cout<<"n=FCFS调度算法=n"for(i=0;i<n;i+)(if(arrivalTimei>nowTime)nowTime=arrivalTimei;nowTime+=serviceTimei;fin

3、ishTimei=nowTime;for(inti=0;i<n;i+)WholeTimei=finishTimei-arrivalTimei;for(inti=0;i<n;i+)WeightWholeTimei=(double)WholeTimei/(double)serviceTimei;for(inti=0;i<n;i+)(averageWT+=(double)WholeTimei/n;averageWWT+=(double)WeightWholeTimei/n;voidSJF()(调度cout<<"n=SJF算法=n"intmin=0;n

4、owTime=arrivalTime0+serviceTime0;finishTime0=nowTime;serviceTime_SJF0=100;intallin=0,j,k;for(i=1;i<n;i+)(k=1;min=0;if(allin=0)(j=0;while(arrivalTimej<=nowTime&&j<n)(j+;if(j>n)allin=1;elsej=n;j=j-1；while(k<=j)(if(serviceTime_SJFk=0)k+;else(if(serviceTime_SJFmin>serviceTime_S

5、JFk)min=k;k+;serviceTime_SJFmin=0;nowTime+=serviceTimemin;finishTimemin=nowTime;for(inti=0;i<n;i+)WholeTimei=finishTimei-arrivalTimei;for(inti=0;i<n;i+)WeightWholeTimei=(double)WholeTimei/(double)serviceTimei;averageWT=0;averageWWT=0;for(inti=0;i<n;i+)averageWT+=(double)WholeTimei/n;average

6、WWT+=(double)WeightWholeTimei/n;voidsortOn()/进程按照到达或者服务时间进行排序inttemp;for(inti=0;i<n;i+)for(intk=0;k<n-i-1;k+)if(arrivalTimek+1<arrivalTimek)temp=arrivalTimek+1;arrivalTimek+1=arrivalTimek;arrivalTimek=temp;temp=serviceTimek+1;serviceTimek+1=serviceTimek;serviceTimek=temp;voidinput()(cout<

7、;<"请输入进程的个数："cin>>n;cout<<endl;while(n>100|n<=0)(cout<<"进程个数必须大于0且小于等于100!请重新输入进程个数"<<endl;cout<<"请输入这"<<N<<”个进程的到达时间：nn”;for(inti=0;i<n;i+)/设置N个进程的到达时间(intM;cin>>M;arrivalTimei=M;cout<<endl;cout<<&

8、quot;请输入这"<<N<<"个进程的对应的服务时间：nn"for(inti=0;i<n;i+)/设置N个进程的服务时间(intM;cin>>M;serviceTimei=M;serviceTime_SJFi=M;cout<<endl;cout<<"您输入的这"<<N<<"个进程的信息如下：nn"sortOn();/进程按照到达时间进行排序cout<<"进程名tt"for(inti=0;i<n;i

9、+)(charc=i+65;cout<<c<<"t"cout<<"n到达时间t"for(inti=0;i<n;i+)cout<<arrivalTimei<<"t”;cout<<"n服务时间t"for(inti=0;i<n;i+)cout<<serviceTimei<<"t"cout<<endl<<endl;voidoutput()cout<<"进程名tt

10、"for(inti=0;i<n;i+)charc=i+65;cout<<c<<"t"cout<<"平均n到达时间t"for(inti=0;i<n;i+)cout<<arrivalTimei<<"t"cout<<"n服务时间t"for(inti=0;i<n;i+)cout<<serviceTimei<<"t"cout<<"n完成时间t”;for(inti

11、=0;i<n;i+)cout<<finishTimei<<"t”;cout<<"n周转时间t”;for(inti=0;i<n;i+)cout<<WholeTimei<<"t"cout<<averageWT<<setprecision(3)<<"n带权周转时间t"for(inti=0;i<n;i+)cout<<WeightWholeTimei<<"t"cout<<aver