作业调度算法源代码

作业调度算法源代码

#include

#include

#define ReadyLimit 5

typedef struct job{

int id;

int needtime;

int arrivetime;

int starttime;

int finishtime;

int remainder;

float priority;

struct job *next;

} jobnode,*jobnodeptr;

jobnodeptr joblist,readylist,runlist,collectlist; int systime;

void init(void)

{

joblist=(jobnodeptr)malloc(sizeof(jobnode)); joblist->id=-1;

joblist->next=NULL;

readylist=(jobnodeptr)malloc(sizeof(jobnode)); readylist->id=-1;

readylist->next=NULL;

collectlist=(jobnodeptr)malloc(sizeof(jobnode));

collectlist->id=-1;

collectlist->next=NULL;

runlist=NULL;

systime=-1;

}

void file2joblist(void)

{

FILE *fp;

jobnodeptr p,q;

int i,j;

fp=fopen("input.txt","rt");

if (!fp){

printf("Can't open file");

exit(1);

}

p=joblist;

fscanf(fp,"%d",&i);

for (j=0;j

q=(jobnodeptr)malloc(sizeof(jobnode));

fscanf(fp,"%d%d%d",&q->id,&q->needtime,&q->arrivetime); q->starttime=0;

q->finishtime=0;

q->remainder=q->needtime;

q->priority=-1.0;

p->next=q;

p=q;

}

p->next=NULL;

fclose(fp);

}

void jobdispatch(void)/*作业调度*/

{

jobnodeptr p,q;

int count=0;

float maxpri;

p=readylist;/*计算readylist中进程的个数*/

while (p->next){

count++;

p=p->next;

}

if (count>=ReadyLimit) return;

p=joblist->next;/*计算已到达作业的响应比*/

while (p){

if (p->arrivetime<=systime)

p->priority=(systime-p->arrivetime)/(float)p->needtime; p=p->next;

}

while (count

maxpri=-1.0;

p=joblist;

q=NULL;

while (p->next){

if (p->next->priority > maxpri){

maxpri = p->next->priority; q = p;

}

p=p->next;

}

if (q){

p=q->next;

q->next=p->next;

p->next=NULL;

q=readylist;

while (q->next)

q=q->next;

q->next=p;

p->starttime=systime;

count++;

}else break;

}

}

void processdispatch(void)/*进程调度*/

{

runlist=readylist->next;

if (runlist) {

readylist->next=runlist->next;

runlist->next=NULL;

}

}

void running(void)/*模拟运行*/

{

jobnodeptr p;

if (runlist){

printf("%4d:%-4d ",systime,runlist->id);

runlist->remainder--;

if (runlist->remainder){

p=readylist;

while (p->next)

p=p->next;

p->next=runlist;

}else{

runlist->finishtime=systime;

p=collectlist;

while (p->next

&& (p->next->starttime < runlist->starttime) /*&& (p->next->id < runlist->id)*/)

p=p->next;

runlist->next=p->next;

p->next=runlist;

}

runlist=NULL;

}else printf("%4d:idle ",systime);

}

void display(void)/*显示信息*/

{

jobnodeptr p;

printf("id----- need--- arrive- start-- finish-\n");

p=collectlist->next;

while (p){

printf("%-7d %-7d %-7d %-7d %-7d\n",p->id,\

p->needtime,p->arrivetime,p->starttime,p->finishtime); p=p->next;

}

}

void freeall(void)

{

jobnodeptr p,q;

p=collectlist;

while (p){

q=p;

p=p->next;

free(q);

}

free(joblist);

free(readylist);

}

int main(void)

{

init();

file2joblist();

while (1){

systime++;

jobdispatch();

processdispatch();

running();

if (joblist->next==NULL && readylist->next==NULL)

break;

}

printf("\n\n"); display();

freeall();

getchar();

return 0;

}