内存分配算法

//⑴自定义内存管理策略对应的数据结构；//⑵随机产生一组申请和收回进程及要求分配和收回内存的大小，实现内存分配和收回算法（可以采用多种分配算法），计算内存利用率；//⑶显示内存分区管理的分配和收回过程。

#include<iostream>#include<cmath>#include<iomanip.h>#include<time.h>#define Size 4#define num 10#define SUCCESS 1#define ERROR -1typedef int byte;typedef struct {byte subareaSize;//分区大小int startLoc;//起始地址int index;// 分区号}SubareaTable;//分区表typedef struct node{// 结点SubareaTable subarea;// 分区struct node *next;int status;//状态位0(空闲)1(使用)}*Node,*LinkList;typedef struct {byte processSize;int subareaIndex;//保存分区号int status;//进程状态,0(新建)1(执行)-1(终止)-2(未绪。

申请但没有分配内存)2(就绪，已分配内存)}Process;//进程int subareaSize[num]={8,12,16,32,24,16,64,128,40,64};//分区大小Process *pro=NULL;//保持进程信息int ProcessNum=0;//进程数目int applyProcessNum=0;//每次申请进程数目int maxApplyNum=0;//最大可申请数目int *applyIndex=NULL;//申请进程队列int totalApplyNum=0;//申请总数int *assignPointer=NULL;//已分配内存的进程队列int assignFlag=0;//分配索引，表示已申请队列已分配的进程数int exeIndex;//执行的进程号Node *subareaNode=new Node[3];//分区回收时，进程所在分区及其前，后分区信息LinkList createLinkList(int n );//建立空闲分区链Node firstFit(LinkList &head,Process pro);//首次适应算法Node nestFit(LinkList &head,Process pro,Node flag);//循环适应算法Node bestFit(LinkList &head,Process pro);//最佳适应算法Node worstFit(LinkList &head,Process pro);//最坏适应算法Node assign(LinkList &head,int orderIndex,int index,Node flagNode);//一次分区分配int assignMemory(LinkList &head);//内存分配void insertNode(LinkList &head,Node q,int index);//插入节点Node deleteNode(LinkList &head,int index);//删除节点int display(LinkList &head);//打印分区分配情况int lowAttemper(int *excursionPointer);//低级调度int findSubarea(LinkList &head,int index);//回收内存int menu();//菜单int creatProcess();//创建进程Process* randomCreatPro(int n);//随机产生进程LinkList createLinkList(int n){//建立空闲分区链cout<<" -------------创建分区--------------"<<endl;LinkList head;Node p;head=(LinkList)malloc(sizeof(node));if(head==NULL){cout<<"头结点分配错误"<<endl;return NULL;}head->next=NULL;//链表尾巴设置为NULLLinkList q=head;int start=0;for(int i=1;i<=n;i++){p=(Node)malloc(sizeof(node));if(p==NULL){cout<<"节点分配错误"<<endl;return NULL;}p->next=q->next;q->next=p;q=p;p->subarea.index=i;p->subarea.subareaSize=subareaSize[i-1];//分区表赋值大小p->subarea.startLoc=start;p->status=0;start+=subareaSize[i-1];}cout<<"分区创建成功!!!"<<endl;return head;}Node firstFit(LinkList &head,Process pro){//首次适应算法Node p=head->next;//遍历结点，返回结点,从第一个结点开始遍历if(p==NULL){cout<<"空闲链表不存在"<<endl;return NULL;}else{do{if(p->status==0&&p->subarea.subareaSize>=pro.processSize){break;}p=p->next;}while(p!=NULL);if(p==NULL){//没找到合适的结点return head;}return p;}}Node nestFit(LinkList &head,Process pro,Node flag){//循环适应算法Node p=flag->next;//遍历结点while(p!=NULL){if(p->status==0&&p->subarea.subareaSize>=pro.processSize){break;}p=p->next;}if(p==NULL){//遍历到链表结尾p=head;//从头开始遍历while(p!=flag){//标记结点p=p->next;if(p->status==0&&p->subarea.subareaSize>=pro.processSize){break;}}if(p==flag){//正常跳出循环，没有合适的结点可分配return head;}else{return p;// 在flag结点前找到一合适的结点分配}}else{return p;// 在flag结点后找到一合适的结点分配}}Node bestFit(LinkList &head,Process pro){//最佳适应算法Node p=head->next;//遍历结点，返回结点,从第一个结点开始遍历Node q;//返回最佳空闲结点int leave;//剩余空间int count=0;//计数器if(p==NULL){cout<<"空闲链表不存在"<<endl;return NULL;}else{do {if(p->status==0&&p->subarea.subareaSize>=pro.processSize){count++;if(count==1){//第一个可以分配的空闲分区leave=p->subarea.subareaSize-pro.processSize;q=p;}else if(count>1){if(p->subarea.subareaSize-pro.processSize<leave){//更适合的结点leave=p->subarea.subareaSize-pro.processSize;q=p;}}}p=p->next;}while(p!=NULL);return q;}}Node worstFit(LinkList &head,Process pro){//最坏适应算法Node p=head->next;//遍历结点，返回结点,从第一个结点开始遍历Node q;//返回最大空闲结点int count=0;//计数器if(p==NULL){cout<<"空闲链表不存在"<<endl;return NULL;}else {// 开始遍历do {if(p->status==0){count++;if(count==1){//第一个空闲区q=p;}else{//非第一个空闲区if(p->subarea.subareaSize>q->subarea.subareaSize){//当前结点大于前面最大结点q=p;}}}p=p->next;}while(p!=NULL);if(q->subarea.subareaSize>=pro.processSize){return q;}else{cout<<"进程大小大于最大分区，无法分配"<<endl;return head;}}}void insertNode(LinkList &head,Node q,int index) {Node p;//遍历结点int j=1;if(head==NULL){cout<<"链表为空";return;}p=head->next;for(;p;p=p->next){j++;if(j>=index)break;}q->next=p->next;p->next=q;//插入完成j=q->subarea.index;//j保持q的分区号q=q->next;//开始修改分区号j=q->subarea.index;while(q!=NULL){q->subarea.index=j+1;q=q->next;j++;}}Node deleteNode(LinkList &head,int index){ Node q;//保存要删掉的节点Node p=head;//遍历的节点int count=0;while(p&&count<index-1){p=p->next;count++;}q=p->next;p->next=q->next;}int findSubarea(LinkList &head,int index){Node p=head->next;//遍历结点if(p==NULL){cout<<"空闲链表不存在"<<endl;return ERROR;}else{int j=1;for(;p;j++){p=p->next;if(j>=index-1)break;}for(int i=0;i<3;i++){subareaNode[i]=p;p=p->next;}return SUCCESS;}}int display(LinkList &head){//打印分区分配情况cout<<" -------------分区信息--------------"<<endl;Node p;if(head==NULL){cout<<"分区未创建,请先创建分区"<<endl;return ERROR;}else{p=head->next;cout.fill(' ');while(p!=NULL){cout.width(3);cout<<p->subarea.index<<"分区的大小:"<<setw(5)<<p->subarea.subareaSize<<"KB "<<"分区开始位置:"<<setw(6)<<p->subarea.startLoc<<"是否空闲:"<<setw(4)<<p->status<<endl;p=p->next;return SUCCESS;}}int displayProcess(){cout<<" -------------进程信息--------------"<<endl;if(pro==NULL){cout<<"进程未创建，请先创建进程"<<endl;return ERROR;}for(int i=0;i<ProcessNum;pro++,i++){cout<<i+1<<"号进程大小:"<<setw(6)<<pro->processSize<<" 进程状况:"<<setw(6);if(pro->status==0){cout<<"创建";}else if(pro->status==1){//进程状态cout<<"执行";}else if(pro->status==-1){cout<<"终止";}else if(pro->status==2){cout<<"就绪";}else if(pro->status==-2){cout<<"未绪";}cout<<endl;}pro-=ProcessNum;return SUCCESS;}int applyforProcess(){cout<<" -------------申请进程--------------"<<endl;int index;if(pro==NULL){cout<<"进程未创建,请先创建进程"<<endl;return ERROR;}cout<<"输入申请进程的数目：";cin>>applyProcessNum;while(applyProcessNum>maxApplyNum){//申请数目大于最大可申请数目cout<<"申请进程数目大于可申请进程数目，不合法"<<endl;cout<<"请重新输入申请进程数:";cin>>applyProcessNum;}displayProcess();for(int i=0;i<applyProcessNum;){cout<<"请输入需要申请的进程(创建进程才能申请):";cin>>index;pro+=(index-1);//修改指针if(pro->status==0){cout<<index<<"号进程申请成功"<<endl;applyIndex[i+totalApplyNum]=index-1;//保持申请进程的偏移量pro->status=-2;//改状态i++;maxApplyNum--;}else{cout<<index<<"号进程不为创建状态，重新申请"<<endl;}pro-=(index-1);//回首址}totalApplyNum+=applyProcessNum;return SUCCESS;}int assignMemory(LinkList &head){//分配内存int n;Node flagNode;if(applyProcessNum==0||head==NULL){cout<<"未申请进程或未建分区....."<<endl;return ERROR;}do{cout<<"**********内存分配**********"<<endl;cout<<setw(10)<<"1.首次适应算法"<<endl;cout<<setw(10)<<"2.循环适应算法"<<endl;cout<<setw(10)<<"3.最佳适应算法"<<endl;cout<<setw(10)<<"4.最坏适应算法"<<endl;cout<<"**************************"<<endl;cout<<"请选择:";cin>>n;}while(n<1||n>4);int count=0;//第一次分配，从头结点开始，其他重上次分配的节点开始applyIndex+=assignFlag;//从分配资源的进程开始分配for(int i=assignFlag;i<totalApplyNum;i++,applyIndex++){if(n!=2){assign(head,n,*applyIndex,NULL);}//head头结点（链表），n(分配算法)NULL(n!=2无作业)，*applyIndex申请进程的偏移指针else if(n==2){if(count==0){flagNode=assign(head,n,*applyIndex,head);count++;}else{flagNode=assign(head,n,*applyIndex,flagNode);}}assignPointer[i]=*applyIndex;//分配的进程进已分配进程队列}applyIndex-=totalApplyNum;//申请进程的偏移指针回首址assignFlag=totalApplyNum;//修改分配数;return SUCCESS;}Node assign(LinkList &head,int orderIndex,int index,Node flagNode){pro+=index;Process process=*pro;Node assignNode;switch(orderIndex){case 1:{assignNode=firstFit(head,process);break;}case 2:{assignNode=nestFit(head,process,flagNode);break;}case 3:{assignNode=bestFit(head,process);break;}case 4:{assignNode=worstFit(head,process);break;}}pro->subareaIndex=assignNode->subarea.index;//保存进程分配的分区号pro->status=2;//修改状态pro-=index;//指针回到起始位置if(assignNode!=NULL){//找到分配分区if(assignNode->subarea.subareaSize-process.processSize<=Size){//不再切割的分区assignNode->subarea.subareaSize=process.processSize;//修改分区大小}else if(assignNode->subarea.subareaSize-process.processSize>Size){//可再划分分区Node node=(Node)malloc(sizeof(node));SubareaTable *subarea=(SubareaTable*)malloc(sizeof(SubareaTable));//划分新的分区subarea->index=assignNode->subarea.index+1;//分区号subarea->subareaSize=assignNode->subarea.subareaSize-process.processSize;//分区大小subarea->startLoc=assignNode->subarea.startLoc+process.processSize;node->status=0;//分区状态node->subarea=*subarea;insertNode(head, node, assignNode->subarea.index+1);//插入空闲链表}assignNode->status=1;// 修改分区使用return assignNode;}else{return NULL;}}void amendNodedata(Node p,Node q){if(p->status==0&&q->status==0){// 前后两分区都不是空闲分区int j=p->subarea.index;//分区号p->subarea.subareaSize+=(q->subarea.subareaSize+subareaNode[1]->subarea.subareaSize);//修改分区大小p->next=q->next;//修改指针;while(p!=NULL){j++;p->subarea.index=j;p=p->next;}}else if(p->status==1&&q->status==0){//前未空闲后空闲p=subareaNode[1];int j=p->subarea.index;p->subarea.subareaSize+=q->subarea.subareaSize;p->next=q->next;while(p!=NULL){j++;p->subarea.index=j;p=p->next;}}else if(p->status==0&&q->status==1){//前空闲后未空闲int j=p->subarea.index;p->subarea.subareaSize+=subareaNode[1]->subarea.subareaSize;p->next=subareaNode[1]->next;while(p!=NULL){j++;p->subarea.index=j;p=p->next;}}}int callbackMemory(LinkList &head, int index){char n;cout<<index+1<<"进程正在执行...."<<endl;cout<<"进程大小为"<<setw(5)<<(pro+index)->processSize<<" 分配的分区号"<<(pro+index)->subareaIndex<<endl;do{cout<<"是否结束进程Y/N 请输入(y/n)";cin>>n;cout<<endl;}while(n!='y'||n!='Y'||n!='n'||n!='N');if(n=='y'||n=='Y'){findSubarea(head,(pro+index)->subareaIndex);if(subareaNode[2]!=NULL){if(subareaNode[0]->status==1&&subareaNode[2]->status==1){subareaNode[0]->status=0;}else {amendNodedata(subareaNode[0],subareaNode[2]);}}else if(subareaNode[0]==NULL){if(subareaNode[0]->status==0){subareaNode[0]->subarea.subareaSize+=subareaNode[1]->subarea.subareaSize;subareaNode[0]->next=subareaNode[2];}else{subareaNode[0]->status=0;}}return SUCCESS ;}else{cout<<"您没结束进程,进程不释放,分区不回收"<<endl;return ERROR;}}int lowAttemper(int *excursionPointer){cout<<" -------------低级调度--------------"<<endl;if(*excursionPointer<0){cout<<"没有已分配好资源的进程";return ERROR;}else{int n;displayProcess();do{cout<<"请选择一个就绪进程进入CPU";cin>>n;cout<<endl;}while(n<1||n>ProcessNum||(pro+n-1)->status!=2);(pro+n-1)->status=1;//进程状态改变exeIndex=n-1;cout<<"CPU正在调度...."<<endl;cout<<n<<"进程获得处理机,开始执行!!!!!"<<endl;return SUCCESS;}}int menu(){int n;do{cout<<"*********************计算机内存管理****************"<<endl;cout<<setw(30)<<"1.创建进程"<<endl;cout<<setw(30)<<"2.进程信息"<<endl;cout<<setw(30)<<"3.进程申请"<<endl;cout<<setw(30)<<"4.分区创建"<<endl;cout<<setw(30)<<"5.内存分配"<<endl;cout<<setw(30)<<"6.内存回收"<<endl;cout<<setw(30)<<"7.打印分区"<<endl;cout<<setw(30)<<"8.低级调度"<<endl;cout<<setw(30)<<"9.系统退出"<<endl;cout<<"***************************************************"<<endl;cout<<"请选择:";cin>>n;}while(n<1||n>9);return n;}int creatProcess(){cout<<" -------------创建进程--------------"<<endl;cout<<"输入进程数目:";cin>>ProcessNum;applyIndex=new int[ProcessNum];//初始化进程申请队列assignPointer=new int[ProcessNum];//初始化进程分配队列maxApplyNum=ProcessNum;pro=randomCreatPro(ProcessNum);cout<<"进程正在创建......"<<endl;return SUCCESS;}Process* randomCreatPro(int n){Process *process=new Process[n];srand((unsigned)time(NULL));//播一次种for(int i=0;i<n;i++){process[i].processSize=1+rand()%128;//随机产生进程的大小process[i].status=0;//初始化进程状况process[i].subareaIndex=-1;//初始化分区号，-1未分配，进程在外存上}return process;void main(){int number=menu();bool flag=true;LinkList head;while(flag){switch(number){case 1: {if(creatProcess()==SUCCESS){cout<<"进程创建完成!!!"<<endl;}break;}case 2:{displayProcess();break;}case 3:{applyforProcess();break;}case 4:{head=createLinkList(num);break;}case 5:{assignMemory(head);break;}case 6:{callbackMemory(head,exeIndex);break;}case 7:{display(head);break;}case 8:{lowAttemper(assignPointer);break;}case 9:{flag=false;cout<<"系统退出!!!";}}if(flag){number=menu();}}}。