进程调度实验

实验目的

进程调度是处理机管理的核心内容。本实验要求用C语言编写和调试一个简单的进程调度程序。通过本实验可以加深理解有关进程控制块、进程队列的概念，并体会和了解优先数和时间片轮转调度算法的具体实施办法。

一、实验内容

实验内容（优先数和时间片轮转调度算法）

①设计进程控制块PCB表结构，分别适用于优先数调度算法和时间轮转调度算法。

②建立进程就绪队列。对两种不同算法编制入链子程序。

③编制两种进程调度算法：1）优先数调度；2）循环轮转调度

二、程序流程图

主程序的流程图:

主要函数模块的流程图：

三、代码实现：

#include<stdio.h>
#include<stdlib.h>
#define N 5
typedef struct pcb
{
	int pid;
	int pyouxian;
	int pdaxiao;
	int CPUtime;
	int needtime;
	int pyouxian_max;
}PCB;
void Creat_process(PCB *);
void Youxian_diaodu(PCB *);
void Shijianpian_diaodu(PCB *);
void Output_process(PCB *);
main()
{
	PCB process[N];
	Creat_process(process);
	Youxian_diaodu(process);
	getchar();//一定要加这句才能运行Shijianpian_diaodu(),因为要考虑输入结束符非't'字符后还有个回车，它就是用来接受回车符！否则回车符会被Shijianpian_diaodu()接受，与预期不符！
	Shijianpian_diaodu(process);
}
void Creat_process(PCB *process)
{
	int i;
	for(i=0;i<N;i++)
	{
		process[i].pid=i+1;
		//printf("\nPlease input this process[%d].pid:\n",i);
		//scanf("%d",&process[i].pid);
		//printf("\nPlease input this process[%d].pyouxian:\n",i);
		//scanf("%d",&process[i].pyouxian);
		process[i].pyouxian=40+rand()%30;
		//printf("\nPlease input this process[%d].pdaxiao:\n",i);
		//scanf("%d",&process[i].pdaxiao);
		process[i].pdaxiao=rand()%300;
		process[i].CPUtime=0;
		process[i].needtime=10+rand()%20;
		process[i].pyouxian_max=0;
	}
	for(i=0;i<N;i++)
	{
		printf("\npid\tpyouxian\tpdaxiao\t\tCPUtime\t\tneedtime\tyxmax\n");
		printf("\n%d\t%d\t\t%d\t\t%d\t\t%d\t\t%d\n",process[i].pid,process[i].pyouxian,process[i].pdaxiao,process[i].CPUtime,process[i].needtime,process[i].pyouxian_max);
	}
}
void Youxian_diaodu(PCB *process)
{
	int i,k;
	char temp;
	printf("\nThis is Youxian_diaodu!\nWhen you input is not:'t',then this fuction stop!\n");
	printf("\nWhen you input 't',then run once:");
	temp=getchar();
	while(/*temp!='z'&&*/temp=='t')
	{
		for(i=0;i<N;i++)
		{
			if(process[i].pyouxian<=0||process[i].needtime<=0)
			{
				printf("\nThe %dth process is over!\n",process[i].pid);
				temp='z';//只要是非't'字符即可!
				break;
			}
		}
		if(temp=='z')//要与前一个非't'字符一致!，因为这里只控制由于process[i].needtime<=0的情况下的处理方式!
		{
			break;
		}
		k=process[0].pid;
		for(i=1;i<N;i++)
		{
			if(process[i].pyouxian>process[k-1].pyouxian)
			{
				k=process[i].pid;
			}
			if(process[i].pyouxian==process[k-1].pyouxian)
			{
				k=process[k-1].pid;
			}
		}
		process[k-1].pyouxian_max=1;
		for(i=0;i<N;i++)
		{
			if(process[i].pyouxian_max==1)
			{
				process[i].pyouxian-=3;
				process[i].CPUtime+=1;
				process[i].needtime-=1;
			}
		}
		Output_process(process);
		process[k-1].pyouxian_max=0;
		getchar();
		temp=getchar();	
	}
}
void Shijianpian_diaodu(PCB *process)
{
	int i,j=0;//,k;
	char temp;
	printf("\nThis is Shijianpian_diaodu!\nWhen you input is not:'t',then this fuction stop!\n");
	printf("\nWhen you input 't',then run once:");
	temp=getchar();
	while(/*temp!='z'&&*/temp=='t')
	{
		for(i=0;i<N;i++)
		{
			//if(process[i].pyouxian<=0||process[i].needtime<=0)
			if(process[i].needtime<=0)
			{
				printf("\nThe %dth process is over!\n",process[i].pid);
				temp='z';//只要是非't'字符即可!
				break;
			}
		}
		if(temp=='z')//要与前一个非't'字符一致!，因为这里只控制由于process[i].needtime<=0的情况下的处理方式!
		{
			break;
		}
		/*k=process[0].pid;
		for(i=1;i<N;i++)
		{
			if(process[i].pyouxian>process[k-1].pyouxian)
			{
				k=process[i].pid;
			}
			if(process[i].pyouxian==process[k-1].pyouxian)
			{
				k=process[k-1].pid;
			}
		}
		process[k-1].pyouxian_max=1;*/
		//for(i=0;i<N;i++)
		//{
			//if(process[i].pyouxian_max==1)
			//{
				//process[i].pyouxian-=3;
				for(i=0;i<N;i++)
				{
					process[i].pyouxian_max=0;//为了把Youxian_diaodu()中的pyouxian_max属性都清零，否则影响此Shijianpian_diaodu()中的pyouxian_max属性！
				}
				process[j].CPUtime+=2;//注意这里的两个数组元素的下标不能同为j++,否则相当于j+=2；
				process[j].needtime-=2;
				process[j].pyouxian_max=1;
			//}
		//}
		Output_process(process);
		process[j].pyouxian_max=0;
		if(j==N-1)
		{
			j=-1;//这里j应为-1，因为下面有j++;语句!
		}
		j++;//别忘了让数组下标指向下一个数组。
		getchar();
		temp=getchar();	
	}
}
void Output_process(PCB *process)
{
	int i;
	for(i=0;i<N;i++)
	{
		printf("\npid\tpyouxian\tpdaxiao\t\tCPUtime\t\tneedtime\tyxmax\n");
		printf("\n%d\t%d\t\t%d\t\t%d\t\t%d\t\t%d\n",process[i].pid,process[i].pyouxian,process[i].pdaxiao,process[i].CPUtime,process[i].needtime,process[i].pyouxian_max);
	}
}

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