操作系统课程设计之处理机调度_编写并实现对n个进程使用动态优先权算法的进程调度c语言

用C语言编写实现对n个进程采用动态优先权算法的进程调度模拟程序。

1.首先设计定义变量

1. 进程标识号：PID
2. 进程名：PNAME
3. 进程优先数SUPER，并规定优先数越大的进程，其优先权越高；假定在调度过程中，进程每运行一个时间片，其优先数减2；进程每在就绪队列中待一个时间片，则其优先数加1。(可自行设定动态优先数的变化规律)
4. 进程已占用的CPU时间RUNTIME（rtime）。 
5. 进程最大需占用的CPU时间NEEDTIME(ntime)。当RUNTIME等于NEEDTIME时，进程运行完毕。

        进程状态STATE。假设实验中的进程只有三种状态：就绪（Wait）、运行（Running）和完成（Finished）。

2.设计所需结构体和函数

定义进程控制块PCB

struct pcb  /*定义进程控制块PCB*/
{	char name[10];  /*进程名*/
	char state;    /*状态：R-运行，W-就绪，F-完成*/
	int super;    /*优先数*/
	int ntime;   /*所需运行时间 need time*/
	int rtime;  /*已经运行时间  run time*/
	struct pcb * next;  
}*ready=NULL,*p;   /* ready指向就绪队列，P指向当前节点 */
typedef struct pcb PCB;

对进程进行优先级排列函数

void sort(){
 PCB *first, *second;
 int insert = 0;
 if ((ready == NULL) || ((p->super) > (ready->super))) //优先级最大者,插入就绪队列队首
 {
  p->next =ready;//插入的数据作为链表头结点
  ready = p;//头结点指针指向插入数
 }
 else //进程比较优先级,插入适当的位置中
 {
  first = ready;
  second = first->next;
  while (second != NULL)
  {
   if ((p->super) > (second->super)) //若插入进程比当前进程优先数大
   { //插入到当前进程前面
    p->next = second;
    first->next = p;
    second = NULL;
    insert = 1;
   }
   else//插入进程优先数最低,则插入到队尾
   {
    first = first->next;
    second = second->next;
   }
  }
  if (insert == 0)
   first->next = p;
 }
}

输入进程控制块函数

void input()
{
int n; 
printf("Please Input the Number of Process:");
scanf("%d",&n);
for(int i=0;i<n;i++){
printf("process id No.%d\n",i+1);
p=getpch(PCB);
printf("process name:");
scanf("%s", p->name);
printf("process priority:");
scanf("%d", &p->super);
printf("process need running time:");
scanf("%d", &p->ntime);
p->rtime=0;
p->state='W';
p->next=NULL;
sort();
}
}

获取就绪状态的进程数

int space()
{
int len=0;
PCB* pr=ready;
while (pr!=NULL)
{
len++;
pr = pr->next;
}
return(len);
}

展示进程各个变量的具体内容

void disp(PCB * pr) 
{
 printf("\n name	 state	 super	 ntime	 rtime\n");
 printf(" %s\t", pr->name);
 printf(" %c\t", pr->state);
 printf(" %d\t", pr->super);
 printf(" %d\t", pr->ntime);
 printf(" %d\t", pr->rtime);
 printf(" \n");
}

查看进程信息，显示当前处于运行态的进程和处于就绪队列的进程

void look()
{
 PCB* pr;
 printf("\n**** the running process is:%s", p->name);
 disp(p);
 pr = ready;
 printf("\n**** the ready process is:\n");
 while (pr != NULL)
 {
  disp(pr);
  pr = pr->next;
 }
}

建立进程就绪函数(进程运行时间到，置就绪状态)

void running()
{
 PCB *pr;
 (p->rtime)++;
   pr=ready;
  while(ready!=NULL){
  	(ready->super)++;
  	ready=ready->next;
  }ready=pr;
 if (p->rtime == p->ntime)
 {
 printf("\n process[%s] is finished.\n", p->name);
 free(p);
 }
 else
 {
  (p->super)=(p->super)-2;
  p->state = 'W';
  sort();
 }
}

下面为程序源代码

#include <stdio.h>
#include <stdlib.h>
#include <malloc.h>
#define getpch(type) (type *)malloc(sizeof(type))
 
struct pcb  /*定义进程控制块PCB*/
{	char name[10];  /*进程名*/
	char state;    /*状态：R-运行，W-就绪，F-完成*/
	int super;    /*优先数*/
	int ntime;   /*所需运行时间 need time*/
	int rtime;  /*已经运行时间  run time*/
	struct pcb * next;  
}*ready=NULL,*p;   /* ready指向就绪队列，P指向当前节点 */
typedef struct pcb PCB;
 
//对进程进行优先级排列函数
void sort(){
 PCB *first, *second;
 int insert = 0;
 if ((ready == NULL) || ((p->super) > (ready->super))) //优先级最大者,插入就绪队列队首
 {
  p->next =ready;//插入的数据作为链表头结点
  ready = p;//头结点指针指向插入数
 }
 else //进程比较优先级,插入适当的位置中
 {
  first = ready;
  second = first->next;
  while (second != NULL)
  {
   if ((p->super) > (second->super)) //若插入进程比当前进程优先数大
   { //插入到当前进程前面
    p->next = second;
    first->next = p;
    second = NULL;
    insert = 1;
   }
   else//插入进程优先数最低,则插入到队尾
   {
    first = first->next;
    second = second->next;
   }
  }
  if (insert == 0)
   first->next = p;
 }
}
 
void input()
{
int n; 
printf("Please Input the Number of Process:");
scanf("%d",&n);
for(int i=0;i<n;i++){
printf("process id No.%d\n",i+1);
p=getpch(PCB);
printf("process name:");
scanf("%s", p->name);
printf("process priority:");
scanf("%d", &p->super);
printf("process need running time:");
scanf("%d", &p->ntime);
p->rtime=0;
p->state='W';
p->next=NULL;
sort();
}
}
 
int space()
{
int len=0;
PCB* pr=ready;
while (pr!=NULL)
{
len++;
pr = pr->next;
}
return(len);
}
 
void disp(PCB * pr) 
{
 printf("\n name	 state	 super	 ntime	 rtime\n");
 printf(" %s\t", pr->name);
 printf(" %c\t", pr->state);
 printf(" %d\t", pr->super);
 printf(" %d\t", pr->ntime);
 printf(" %d\t", pr->rtime);
 printf(" \n");
}
 
void look()
{
 PCB* pr;
 printf("\n**** the running process is:%s", p->name);
 disp(p);
 pr = ready;
 printf("\n**** the ready process is:\n");
 while (pr != NULL)
 {
  disp(pr);
  pr = pr->next;
 }
}
 
void running()
{
 PCB *pr;
 (p->rtime)++;
   pr=ready;
  while(ready!=NULL){
  	(ready->super)++;
  	ready=ready->next;
  }ready=pr;
 if (p->rtime == p->ntime)
 {
 printf("\n process[%s] is finished.\n", p->name);
 free(p);
 }
 else
 {
  (p->super)=(p->super)-2;
  p->state = 'W';
  sort();
 }
}
 
main( )
{	int len, h=0;  /*len存放就绪进程的数量，h为运行的时间片序号*/
	char ch;
	input( );   /*接收用户输入，建立ready指向的进程链表*/
	len=space( );   /*获取就绪状态的进程数*/
	while((len!=0)&&(ready!=NULL))
	{	ch=getchar( );
		h++;
		printf("\n The execute number:%d",h);
		p=ready;  /*运行就绪队列的队首进程*/
		ready=p->next; /*更改就绪队列指针*/
		p->next=NULL; /*摘下队首进程*/
		p->state='R';  /*置为运行状态*/
		look( );    /*查看并显示运行和就绪的进程信息*/
		running( ); 
		printf("\n please press any key to continue......");
		ch=getchar( );
	}
	printf("\n\n All processes are finished.\n");
	ch=getchar( );
}

运行结果：