C语言实现多级反馈队列调度算法

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
typedef struct node   /*进程节点信息*/
{
char name[20];   /*进程的名字*/
int prio;    /*进程的优先级*/
int round;    /*分配CPU的时间片*/
int cputime;   /*CPU执行时间*/
int needtime;   /*进程执行所需要的时间*/
char state;    /*进程的状态，W——就绪态，R——执行态，F——完成态*/
int count;    /*记录执行的次数*/
struct node *next;  /*链表指针*/
}PCB;
typedef struct Queue  /*多级就绪队列节点信息*/
{
PCB *LinkPCB;   /*就绪队列中的进程队列指针*/
int prio;    /*本就绪队列的优先级*/
int round;    /*本就绪队列所分配的时间片*/
struct Queue *next;  /*指向下一个就绪队列的链表指针*/
}ReadyQueue;
PCB *run=NULL,*finish=NULL; /*定义三个队列，就绪队列，执行队列和完成队列*/
ReadyQueue *Head = NULL; /*定义第一个就绪队列*/
int num;     /*进程个数*/
int ReadyNum;    /*就绪队列个数*/
void Output();          /*进程信息输出函数*/
void InsertFinish(PCB *in);       /*将进程插入到完成队列尾部*/
void InsertPrio(ReadyQueue *in);     /*创建就绪队列，规定优先数越小，优先级越低*/
void PrioCreate();         /*创建就绪队列输入函数*/
void GetFirst(ReadyQueue *queue);     /*取得某一个就绪队列中的队头进程*/
void InsertLast(PCB *in,ReadyQueue *queue);   /*将进程插入到就绪队列尾部*/
void ProcessCreate();        /*进程创建函数*/
void RoundRun(ReadyQueue *timechip);    /*时间片轮转调度算法*/
void MultiDispatch();        /*多级调度算法，每次执行一个时间片*/

int main(void)
{
PrioCreate(); /*创建就绪队列*/
ProcessCreate();/*创建就绪进程队列*/
MultiDispatch();/*算法开始*/
Output();  /*输出最终的调度序列*/
return 0;
}
void Output()  /*进程信息输出函数*/
{
ReadyQueue *print = Head;
PCB *p;
printf("进程名/t优先级/t轮数/tcpu时间/t需要时间/t进程状态/t计数器/n");
while(print)
{
if(print ->LinkPCB != NULL)
{
p=print ->LinkPCB;
while(p)
{
printf("%s/t%d/t%d/t%d/t%d/t/t%c/t/t%d/n",p->name,p->prio,p->round,p->cputime,p->needtime,p->state,p->count);
p = p->next;
}
}
print = print->next;
}
p = finish;
while(p!=NULL)
{
printf("%s/t%d/t%d/t%d/t%d/t/t%c/t/t%d/n",p->name,p->prio,p->round,p->cputime,p->needtime,p->state,p->count);
p = p->next;
}
p = run;
while(p!=NULL)
{
printf("%s/t%d/t%d/t%d/t%d/t/t%c/t/t%d/n",p->name,p->prio,p->round,p->cputime,p->needtime,p->state,p->count);
p = p->next;
}

}
void InsertFinish(PCB *in)  /*将进程插入到完成队列尾部*/
{
PCB *fst;
fst = finish;

if(finish == NULL)
{
in->next = finish;
finish = in;
}
else
{
while(fst->next != NULL)
{
fst = fst->next;
}
in ->next = fst ->next;
fst ->next = in;
}
}
void InsertPrio(ReadyQueue *in)  /*创建就绪队列，规定优先数越小，优先级越低*/
{
ReadyQueue *fst,*nxt;
fst = nxt = Head;

if(Head == NULL)    /*如果没有队列，则为第一个元素*/
{
in->next = Head;
Head = in;
}
else       /*查到合适的位置进行插入*/
{
if(in ->prio >= fst ->prio)  /*比第一个还要大，则插入到队头*/
{
in->next = Head;
Head = in;
}
else
{
while(fst->next != NULL)  /*移动指针查找第一个别它小的元素的位置进行插入*/
{
nxt = fst;
fst = fst->next;
}

if(fst ->next == NULL)  /*已经搜索到队尾，则其优先级数最小，将其插入到队尾即可*/
{
in ->next = fst ->next;
fst ->next = in;
}
else     /*插入到队列中*/
{
nxt = in;
in ->next = fst;
}
}
}
}
void PrioCreate() /*创建就绪队列输入函数*/
{
ReadyQueue *tmp;
int i;

printf("输入就绪队列的个数：/n");
scanf("%d",&ReadyNum);

printf("输入每个就绪队列的CPU时间片：/n");
for(i = 0;i < ReadyNum; i++)
{
if((tmp = (ReadyQueue *)malloc(sizeof(ReadyQueue)))==NULL)
{
perror("malloc");
exit(1);
}
scanf("%d",&(tmp->round));  /*输入此就绪队列中给每个进程所分配的CPU时间片*/
tmp ->prio = 50 - tmp->round;  /*设置其优先级，时间片越高，其优先级越低*/
tmp ->LinkPCB = NULL;    /*初始化其连接的进程队列为空*/
tmp ->next = NULL;
InsertPrio(tmp);     /*按照优先级从高到低，建立多个就绪队列*/
}
}
void GetFirst(ReadyQueue *queue)     /*取得某一个就绪队列中的队头进程*/
{
run = queue ->LinkPCB;

if(queue ->LinkPCB != NULL)
{
run ->state = 'R';
queue ->LinkPCB = queue ->LinkPCB ->next;
run ->next = NULL;
}
}
void InsertLast(PCB *in,ReadyQueue *queue)  /*将进程插入到就绪队列尾部*/
{
PCB *fst;
fst = queue->LinkPCB;

if( queue->LinkPCB == NULL)
{
in->next =  queue->LinkPCB;
queue->LinkPCB = in;
}
else
{
while(fst->next != NULL)
{
fst = fst->next;
}
in ->next = fst ->next;
fst ->next = in;
}
}
void ProcessCreate() /*进程创建函数*/
{
PCB *tmp;
int i;

printf("输入进程的个数：/n");
scanf("%d",&num);
printf("输入进程名字和进程所需时间：/n");
for(i = 0;i < num; i++)
{
if((tmp = (PCB *)malloc(sizeof(PCB)))==NULL)
{
perror("malloc");
exit(1);
}
scanf("%s",tmp->name);
getchar();        /*吸收回车符号*/
scanf("%d",&(tmp->needtime));
tmp ->cputime = 0;
tmp ->state ='W';
tmp ->prio = 50 - tmp->needtime;  /*设置其优先级，需要的时间越多，优先级越低*/
tmp ->round = Head ->round;
tmp ->count = 0;
InsertLast(tmp,Head);      /*按照优先级从高到低，插入到就绪队列*/
}
}
void RoundRun(ReadyQueue *timechip)    /*时间片轮转调度算法*/
{

int flag = 1;

GetFirst(timechip);
while(run != NULL)
{
while(flag)
{
run->count++;
run->cputime++;
run->needtime--;
if(run->needtime == 0) /*进程执行完毕*/
{
run ->state = 'F';
InsertFinish(run);
flag = 0;
}
else if(run->count == timechip ->round)/*时间片用完*/
{
run->state = 'W';
run->count = 0;   /*计数器清零，为下次做准备*/
InsertLast(run,timechip);
flag = 0;
}
}
flag = 1;
GetFirst(timechip);
}
}
void MultiDispatch()   /*多级调度算法，每次执行一个时间片*/
{
int flag = 1;
int k = 0;

ReadyQueue *point;
point = Head;

GetFirst(point);
while(run != NULL)
{
Output();
if(Head ->LinkPCB!=NULL)
point = Head;
while(flag)
{
run->count++;
run->cputime++;
run->needtime--;
if(run->needtime == 0) /*进程执行完毕*/
{
run ->state = 'F';
InsertFinish(run);
flag = 0;
}
else if(run->count == run->round)/*时间片用完*/
{
run->state = 'W';
run->count = 0;   /*计数器清零，为下次做准备*/
if(point ->next!=NULL)
{
run ->round = point->next ->round;/*设置其时间片是下一个就绪队列的时间片*/
InsertLast(run,point->next);  /*将进程插入到下一个就绪队列中*/
flag = 0;
}
else
{
RoundRun(point);   /*如果为最后一个就绪队列就调用时间片轮转算法*/
break;
}
}
++k;
if(k == 3)
{
ProcessCreate();
}
}
flag = 1;
if(point ->LinkPCB == NULL)/*就绪队列指针下移*/
point =point->next;
if(point ->next ==NULL)
{
RoundRun(point);
break;
}
GetFirst(point);
}
}