0.cpp

这是我们学习操作系统的时候老师给我们做的关于进程调度的实验

#include <stdlib.h>
#include <time.h>
#include <iostream.h>
struct PCB
{
 int pid;
 int time;          //到达时间
 int runtime;       //运行时间
 int zt;             //状态
 int yx;             //优先级
};
void main()
{
    PCB pcb[4];
    //随机值初始化
   srand((unsigned)time(NULL));
   for(int i=0;i<4;i++)
   {
	   pcb[i].pid=i;
       pcb[i].time=rand()%30;
       pcb[i].runtime=rand()%50;
       pcb[i].zt=rand()%2;
       pcb[i].yx=rand()%20;
   }
   cout<<"1.演示先来先服务"<<endl;
   cout<<"2.演示时间片轮转"<<endl;
   cout<<"3.演示优先级调度"<<endl;
    int j,n,m;
    int w=0;
    cout<<"请选择:";
    cin>>i;
   switch(i)
   {
   case  1 :
	   for(j=0;j<4;j++)
		   for(n=0;n<3;n++)
		   {
			   if(pcb[n].time>pcb[n+1].time)
			   {
                   PCB temp;
                   temp=pcb[n];
                   pcb[n]=pcb[n+1];
                   pcb[n+1]=temp;
			   }
		   }
		   cout<<"PID   到达时间   运行时间  状态  优先级"<<endl;
           for(j=0;j<4;j++)
			   cout<<pcb[j].pid<<"      "<<pcb[j].time<<"          "<<pcb[j].runtime<<"       "<<pcb[j].zt<<"      "<<pcb[j].yx<<endl;
               break;
   case 2:
	   cout<<"PID   到达时间   运行时间  状态  优先级"<<endl;
	   for(j=0;j<4;j++)
		   for(n=0;n<3;n++)
		   {
			   if(pcb[n].runtime>pcb[n+1].runtime)
			   {
                    PCB temp;
                    temp=pcb[n];
                    pcb[n]=pcb[n+1];
                    pcb[n+1]=temp;
			   }
		   }
		   m=pcb[3].runtime;
           while(w!=m+1)
		   {
			   if(w==pcb[0].runtime)
               cout<<pcb[0].pid<<"      "<<pcb[0].time<<"          "<<pcb[0].runtime<<"       "<<pcb[0].zt<<"      "<<pcb[0].yx<<endl;
               if(w==pcb[1].runtime)
               cout<<pcb[1].pid<<"      "<<pcb[1].time<<"          "<<pcb[1].runtime<<"       "<<pcb[1].zt<<"      "<<pcb[1].yx<<endl;
               if(w==pcb[2].runtime)
               cout<<pcb[2].pid<<"      "<<pcb[2].time<<"          "<<pcb[2].runtime<<"       "<<pcb[2].zt<<"      "<<pcb[2].yx<<endl;
               if(w==pcb[3].runtime)
               cout<<pcb[3].pid<<"      "<<pcb[3].time<<"          "<<pcb[3].runtime<<"       "<<pcb[3].zt<<"      "<<pcb[3].yx<<endl;
               w++;
		   }
		   break;
   case 3:
	   cout<<"PID   到达时间   运行时间  状态  优先级"<<endl;
       for(j=0;j<4;j++)
		   for(n=0;n<3;n++)
		   {
                if(pcb[n].yx<pcb[n+1].yx)
				{
                     PCB temp;
                     temp=pcb[n];
                     pcb[n]=pcb[n+1];
                     pcb[n+1]=temp;
				}
		   }
		   for(j=0;j<4;j++)
              cout<<pcb[j].pid<<"      "<<pcb[j].time<<"          "<<pcb[j].runtime<<"       "<<pcb[j].zt<<"      "<<pcb[j].yx<<endl;
         break;
   }
}