进程调度算法实现代码(操作系统)

进程调度算法实现

//数据：进程，队列结构

//处理流程：

//1 初始化--进程队列结构（包括：就绪队列，等待队列，运行队列）等必要的数据结构 init();

//2 进入无限循环，反复调度队列

#define MAX 5

#include

#include

int total_time=20;

int time_slice=3;

typedef struct process { // 进程控制块

char pname[10];

int WaitTime;

int BurstTime;

int priority; // 数字越小优先级越高

struct process *next;

}PROCESS;

//typedef struct process PROCESS;

PROCESS * in_queue(PROCESS *head,PROCESS *p); //声明

PROCESS *init() //进程初始化

{

int i=0;

char a;

PROCESS *head_new; //队列的队头

head_new=(struct process*)malloc(sizeof(struct process));

if(!head_new) exit(1);

head_new=NULL;

do

{

struct process *s;

printf(\"initialize the process:\\n\");

s=(struct process *)malloc(sizeof(struct process));

if(!s) exit(1);

printf(\"please input the pname:WaitTime: BurstTime: scanf(\"%c\

scanf(\"%d\

scanf(\"%d\

scanf(\"%d\

s->next=NULL;

priority:\\n\");

in_queue(head_new,s);

i++;

printf(\"do u want to insert process more ?? 'Y'or'N'\\n\");

printf(\"----------------------------------------'\\n\");

scanf(\"%c\

scanf(\"%c\

// if(a=='Y'||a=='y') continue;

// else if(a=='N'||a=='n') break;

}while((ireturn head_new;

}

///////////////////////////////////////////////////////////

PROCESS *in_queue(PROCESS *head,PROCESS *p) //入队函数

{

if(head==NULL)

{

head=p;

p->next=NULL;

}

else

{

p->next=head;

head=p;

}

// printf(\"the process insert into the mothball queue :\\n\");

return head;

}

/////////////////////////////////////////////////////////////

/*

void new_queue() //后备队列 先来先服务方式进入就绪

{

return *head_new;

}

*/

PROCESS *FCFS_process()

{

PROCESS *p,*q,*a; //a用来记录选中结点的前一个结点

q=p=init(); //这里是不是有个问题？？

while(p->next!=NULL)

{

a=p;

if(p->WaitTime>=q->WaitTime)

{

q=p;

p=p->next;

}

}

q->WaitTime--;

if(q->WaitTime==0) {

a->next=p->next;

free(p);

//如果等待时间为0则把该进程从后备队列中移除

}

return q; //选择等待时间最久的）

}

//////////////////////就绪队列，入口函数为就绪队列的头指针/////////////

int count=0;

PROCESS *ready_queue(PROCESS *head) //就绪队列 优先级进入运行 4道

{

PROCESS *p;

while(count<4)

{

p=FCFS_process();

p->next=head->next;

head=p;

count++;

printf(\"the process has inserted into the ready queue :\\n\");

}

return head;

}

//insert_ready() //

PROCESS *high_priority(PROCESS *P) //选择优先级最高的进程

{

PROCESS *q,*p; //问题，入口形参中

q=p;

while(p->next!=NULL)

{

if(q->priority>p->priority)

q=p;

p=p->next;

}

return q;

}

PROCESS *pick_ready(PROCESS *a) //从就绪队列中选择进程运行

{

PROCESS *p=ready_queue(a);

PROCESS *b=high_priority(p);

return b;

}

void run(PROCESS *a) //运行一个时间片

{

while((time_slice>0)&&(a->BurstTime>0)) //指针用-> 变量用.

{

printf(\"the process %c is runing\

printf(\"the process BurstTime time is %d \

printf(\"the process BurstTime time is %d \

printf(\"the process priority is %d \

a->BurstTime--;

time_slice--;

}

a->priority--;

total_time--;

/*

if(a->runtime>0)

return a;

else return NULL;*/

}

void main()

{

PROCESS *p;

PROCESS *head=init();

while(total_time!=0)

{

ready_queue(head);

p=pick_ready(head);

if(p->BurstTime==0)

{

p=p->next;

free(p);

count--;

}

run(p);

time_slice=3;

}

}