主存的分配和回收

1、/主存的分配和回收 最先适应算法#include<iostream>#include<string>using namespace std;struct Block /空闲链结构体 string name; /作业名 int address; /分区首地址 int size; /分区大小 int state; /分区转态 struct Block *next; /前向指针 struct Block *front; /后向指针;struct Used /已分配分区结构体 Block *usedArea; Used *next; Block * freeHead; / 带表

2、头附加节点的空闲链头指针 Used * usedHead; /带表头附加结点的已分配分区头指针bool InitValue() /初始化函数 cout<<"本程序设立的操作功能：1-申请资源 2-释放资源 3-打印信息"<<endl; freeHead = new Block; freeHead->size=0; freeHead->next=NULL; freeHead->state=1; usedHead=new Used; Block *p=new Block; p->address=0; usedHead->us

3、edArea=p; usedHead->next=NULL; Block *temp=new Block; cout<<"请先输入主存大小(k)："<<endl; cin>>temp->size; temp->address=0; temp->state =0; temp->next=freeHead; temp->front=NULL; freeHead->front=temp; return true;void Display(Block *p,Used *q) /打印信息的函数 cout&l

4、t;<"已分配分区信息(作业,始址,大小):"<<endl; while(q!=NULL) cout<<q->usedArea->name<<','<<q->usedArea->address<<','<<q->usedArea->size<<endl; q=q->next; cout<<"空闲链分区信息(始址,大小)："<<endl; while(p!=NULL) c

5、out<<p->address<<',' cout<<p->size<<endl; p=p->front; void Allocate(string reqName,int reqSize) /分配函数 Block *p=freeHead->front ; Used *r1,*r2; while(p!=NULL) if(reqSize<p->size) /如果请求的分区的大小小于一个空闲分区的大小 Used *temp=new Used; temp->usedArea =p; Block

6、*q=new Block; *q=*p; temp->usedArea ->name =reqName; temp->usedArea ->size =reqSize; temp->usedArea ->front =q; temp->usedArea ->state =1; q->size =q->size -reqSize; q->address =q->address + reqSize; q ->next->front=q; if(q ->front!=NULL) q ->front->

7、;next=q; r1=usedHead; r2=usedHead->next; while(r2!=NULL&&r2->usedArea->address<temp->usedArea->address) r1=r2;r2=r2->next; r1->next=temp; temp->next=r2; break; else if(reqSize=p->size)/如果请求的分区的大小等于一个空闲分区的大小 Used *temp=new Used; temp->usedArea =p; temp->use

8、dArea ->name =reqName; temp->usedArea ->state =1; p->next->front =p->front ; if(p->front!=NULL) p->front ->next =p->next ; r1=usedHead; r2=usedHead->next; while(r2!=NULL&&r2->usedArea->address<temp->usedArea->address) r1=r2;r2=r2->next; r1-&

9、gt;next=temp; temp->next=r2; break; p=p->front; if(p=NULL) cout<<"资源不足 请等待"<<endl;void Recycle(string freeName) /回收分区的函数 Used *p=usedHead->next,*r=usedHead; Block *q; while(p!=NULL) if(p->usedArea->name=freeName)/找到同名的作业后，再分四种情况讨论 q=p->usedArea; int flag1=1,fl

10、ag2=1; Block *p1=freeHead->front; Block *pfront,*pnext; while(p1->address<q->address) if(p1->address+p1->size=q->address)flag1=0;pnext=p1; p1=p1->front; if(q->address+q->size=p1->address) flag2=0;pfront=p1; if(flag1=0) if(flag2=0) pnext->front =pfront->front; p

11、next->size=pnext->size + q->size + pfront->size; if(pfront->front!=NULL) pfront ->front ->next=pnext; r->next =p->next; else pnext ->size +=q->size;r->next =p->next ; else if(flag2 =0) pfront ->address -=q->size; pfront ->size +=q->size ; r->next

12、 =p->next ; else Block *temp=freeHead; while(temp->address <=q->address )temp=temp->front; q->front =temp; q->next =temp->next ; q->next->front =q; temp->next =q; q->state =0; r->next =p->next ; break; r=p; p=p->next ; int main() InitValue(); int operate;/操作符1-申请资源 2-释放资源 3-打印信息 string name; int size; while(1) cout<<"请选择操作功能"<<endl; cin>>operate; if(operate=1) cout<<"请输入作业名(字符串) 空间大小(正整数)"<<endl; cin>>name>>si