process.cpp

操作系统中进程调度试验

#include<stdio.h>
#include<string.h>
#include<stdlib.h>
#include <process.h>   
#include <conio.h> 

typedef struct process
{
	int cputime;
	int p;                 //进程现在的优先数
	int count;             //执行次数
	char name[10];         //进程的名字
	int nt;                //进程执行需要的时间
	int state;             //进程状态 0：就绪 1：运行 2：完成 
	struct process *next;  //指向下一道进程
}PCB;

int round = 0;

void wait()    
{
	printf("\n\n按任意键继续\n");
	getch();
}

void Print(PCB *head)
{
    PCB *p=head->next;
    if(!p)
		printf("NULL");
    else
    {
		printf("\n输入内容为：\n");
		while(p!=NULL)
        {
            printf("%s %d\n",p->name,p->nt);
            p=p->next;
        }
    }
}

PCB *InsertNode(PCB *head,PCB *p)
{//在非递增的有序表中作插入
	PCB *p1,*p2,*p3;
	p1=head->next;
	p2=p3=head;
	while(p1)
	{
		
		if(p1->p < p->p)
		{
			p2->next=p;
			p->next=p1;
			break;
		}
		else
		{
			p1=p1->next;
			p2=p2->next;
		}
	}
	if(p1==NULL)
	{
		p2->next=p;
		p->next=p1;
	}
	return head;
}

PCB *input(int mode)
{
	PCB *p1,*p2,*head;
	head = (PCB *)malloc(sizeof(PCB));
	p1 = (PCB *)malloc(sizeof(PCB));
	printf("INPUT NAME AND NEEDTIME:\n");
	head->next = NULL;
	p2 = head;
	if(mode == 2)
	{
		for(int i = 0; i < 5; i++)
		{
			scanf("%s %d",&p1->name,&p1->nt);
			p1->state = 0;   //将初始状态全部置为就绪状态
			p1->count = p1->cputime = 0;  
			p2->next = p1;  //p2是p1的前驱
			p2 = p1;
			p1 = (PCB *)malloc(sizeof(PCB));
		}
		p2->next = NULL;
	}
	if(mode == 1)
	{
		for(int j = 0; j < 5; j++)
		{//在初始时将进程按照优先级排好队列，为在就绪队列中挑选优先数大的进入运行队列提供方便 
			scanf("%s %d",&p1->name,&p1->nt);
			p1->state = 0;   //将初始状态全部置为就绪状态
			p1->cputime = 0;
			p1->p = 50 - p1->nt;    //初始优先数为50-NEEDTIME
			head = InsertNode(head,p1);
			p1 = (PCB *)malloc(sizeof(PCB));
		}
	}
	Print(head);
	return head;
}

PCB *mynote(PCB *L)
{//将链表中第一个节点放到链表尾部 
	PCB *p,*q;
	if (L->next && L->next->next)
	{
		q = L->next;
		L->next = L->next->next;
		p = L->next;
		while(p->next) 
			p = p->next;
		p -> next = q;
		q->next = NULL;
	}
	return L;
}

void printstate1(PCB *head)
{
	PCB *q;
	printf("\nOUTPUT OF PRIORITY:\n");
	printf("\tNAME   CPUTIME   NEEDTIME   PRIORTY   STATE\n");
	q = head->next;
	while(q)
	{
		printf("\t %s       %d         %d        %d         %d\n",q->name,q->cputime,q->nt,q->p,q->state);
		q = q->next;
	}
}	

void priority(PCB *head)
{
	int pri = 3;       //执行一次后要减少的优先数
	PCB *p,*q;
	p = head->next;
	while(p!=NULL)
	{
		p->state = 1;
		p->p = p->p - 3;
		(p->nt)--;
		(p->cputime)++;
		printstate1(head);
		if(p->nt == 0)//已完成的进程
		{
			p->state = 2;
			printstate1(head);
			if(p == head->next)
			{
				head->next = p->next;
				p = p->next;
			}
			else
			{
				q = head->next;
				while(q->next != p)
					q = q->next;
				q->next = p->next;
				p = p->next;
			}
		}
		else 
		{
			if(p->next != NULL)
			{
				if(p->p > p->next->p)
				{
					p->state = 1;
					printstate1(head);
				}
				else
				{
					p->state = 0;
					printstate1(head);
					p = p->next;
				}
			}
			else
			{
				if(p->p > head->next->p)
				{
					p->state = 1;
					printstate1(head);
				}
				else
				{
					p->state = 0;
					printstate1(head);
					p = head->next;
				}
			}
		}	
	}
}

void printstate2(PCB *head)
{
	PCB *q;
	printf("\nOUTPUT OF ROUNDROBIN:\n");
	printf("\tNAME   CPUTIME   NEEDTIME   COUNT   ROUND   STATE\n");
	q = head->next;
	while(q)
	{
		printf("\t %s       %d         %d        %d        %d       %d\n",q->name,q->cputime,q->nt,q->count,round,q->state);
		q = q->next;
	}
}

void roundrobin(PCB *head)
{
	PCB *p;
	int tp = 2;        //采用时间片轮转时的固定时间片
	int ct = 2;        //进程每执行一次，cpu时间的增加数
	p = head->next;
	char n[10];
	strcpy(n,p->name);
	while(p!=NULL)
	{	
		p->state = 1; //置状态为运行 
		p->nt = (p->nt) - tp; 
		if(p->nt<0)//该进程已经完成，无再需要的时间了。可以把还需要的时间置为0 
			p->nt = 0;
		p->cputime = (p->cputime) + ct; 
		printstate2(head);
		if(strcmp(head->next->name,n)==0)
			round++;
		if(p->nt>0)
		{
			head = mynote(head);//执行未完，排到队列尾部
			p-> state = 0;//重新转为就绪状态
		   (p->count)++;
		    p = head->next;
		} 
		else
		{//执行完毕删除该节点
			p->state = 2;
			printstate2(head);
			head->next = p->next;
			p = p->next;
		}
		printstate2(head);
	}
}

int main()
{
	char p[100];
	PCB *hp,*hr;
	printf("ABOUT STATE: 0 STANDS FOR READY,1 STANDS FOR RUN,2 STANDS FOR FINISH\n");
	printf("\nTYPE THE ALGORITHM：(PRIORITY/ROUNDROBIN):\n");
	gets(p);
	if(strcmp(p,"PRIORITY") == 0)
	{
		hp = input(1);
		priority(hp);
	}
	else if(strcmp(p,"ROUNDROBIN") == 0)
	{
		hr = input(2);
		roundrobin(hr);
	}
	wait();
	return 0;
}