操作系统实验报告-死锁的避免

操作系统实验报告-死锁的避免操作系统实验（二）死锁的避免1•实验内容使用C++实现模拟随机算法和银行家算法2•实验目的（1）了解死锁的产生原因（随机算法）（2）理解死锁的解决办法（银行家算法）3•实验题目使用随机算法和银行家算法设计程序4•程序流程图主要过程流程图银行家算法流程图安全性算法流程图5•程序代码和运行结果#includevstdio・h>#include<stdlib.h>typedefstruct{intA;intB;intC;}RES;#definefalse0#definetrue1〃系统中所有进程数量#definePNUMBER3//最大需求矩阵RESMax[PNUMBER];〃已分配资源数矩阵RESAllocation[PNUMBER];〃需求矩阵RESNeed[PNUMBER];//可用资源向量RESAvailable={0,0,0};〃安全序列intsafe[PNUMBER];voidsetConfig(){inti=0j=0;printf("================开始手动配置资==================\n");//可分配资源printf("输入可分配资源\n");scanf("%d%d%d",&Available.A,&Available.B,&Available.C);〃最大需求矩阵MAXprintf("输入最大需求矩阵%dx%d\n",PNUMBER,PNUMBER);for(i=0;i<PNUMBER;i++){scanf("%d%d%d",&Max[i]・A,&Max[i]・B,&Max[i]・C);}〃已分配矩阵Allocprintf("输入已分配矩阵%dx%d\n",PNUMBER,PNUMBER);for(i=0;i<PNUMBER;i++){scanf("%d%d%d",&Allocation[i].A9&Allocation[i].B9&Allocation[i]・C);}〃需求矩阵printf("输入需求矩阵％dx%d\n"fNUMBERfNUMBER);for(i=O;ivPNUMBER;i++){scanf("%d%d%d",&Need[i]・A,&Need[i]・B,&Need[i]・C);}printf("============结束配置资源==================\n");}voidloadConfig(){FILE*fp1;if((fp1=fOpen("config.txt","r"))==NULL){printf("没有发现配置文件，请手动输入\n");setConfig();}else{inti=0;printf("发现配置文件，开始导入.An");//可分配资源fscanf(fp1,"%d%d%d",&Available・A,&Available・B,&Available・C);〃最大需求矩阵MAXfor(i=0;ivPNUMBER;i++){fscanf(fp1,"%d%d%d",&Max[i]・A,&Max[i]・B,&Max[i]・C);}〃已分配矩阵Allocfor(i=0;ivPNUMBER;i++){fscanf(fp1,"%d%d%d",&Allocation[i]・A,&Allocation[i]・B,&Allocation[i]・C);}〃需求矩阵for(i=0;ivPNUMBER;i++){fscanf(fp1,"%d%d%d",&Need[i]・A,&Need[i]・B,&Need[i]・C);〃试探分配voidProbeAlloc(intprocess,RES*res){Available.A-=res->A;Available.B-=res->B;Available.C-=res->C;Allocation[process].A+=res->A;Allocation[process].B+=res->B;Allocation[process].C+=res->C;Need[process].A-=res->A;Need[process].B-=res->B;Need[process].C-=res->C;}//若试探分配后进入不安全状态，将分配回滚voidRollBack(intprocess,RES*res){Available.A+=res->A;Available.B+=res->B;Available.C+=res->C;Allocation[process].A-=res->A;Allocation[process].B-=res->B;Allocation[process].C-=res->C;Need[process].A+=res->A;Need[process].B+=res->B;Need[process].C+=res->C;}〃安全性检査boolSafeCheck(){RESWork;

Work.A=Available";Work.B=Available.B;Work.C=Available.C;boolintintFinish[PNUMBER]={false,false,false};•i;j=0;for(i=0;i<PNUMBER;i++){/是否已检查过if(Finish[i]==false){/是否有足够的资源分配给该进程if(Need[i].A=Work.A&&Need[i].B<=Work.B&&Need[i]・C<=Work.C){/有则使其执行完成，并将已分配给该进程的资源全部回收Work.A+=Allocation[i].A;Work.B+=Allocation[i].B;Work.C+=Allocation[i].C;Finish[i]=true;safe[j++]=i;}}i=-1;/重新进行遍历}/如果所有进程的Finish向量都为true则处于安全状态，否则为不安全状态for(i=0;i<PNUMBER;i++){if(Finish[i]==false){returnfalse;}}returntrue;}/资源分配请求boolrequest(intprocess,RES*res){//reques向量需小于Need矩阵中对应的向量if(res->A<=Need[process].A&&res->B<=Need[process].B&&res->C<=Need[process].C){//request向量需小于Available向量if(res->A<=Available.A&&res->B<=Available.B&&res->C<=Available.C){〃试探分配ProbeAiloc(process,res);〃如果安全检查成立，则请求成功，否则将分配回滚并返回失败if(SafeCheck()){returntrue;}else{printf("安全性检查失败。原因：系统将进入不安全状态，有可能引起死锁。\n")；printf("正在回滚・・An");RollBack(process,res);}}else{printf("安全性检查失败。原因：请求大于可利用资源。\n");}}else{printf("安全性检查失败。原因：请求大于需求。\n");}returnfalse;}〃输出资源分配表voidPrintTable(){printf("===================================资源分配表==================================\n");printf("ProcessMaxAllocationNeedAvailable\n");printf("ABCABCABCABC\n");printf("P0%2d%2d%2d%2d%2d%2d%2d%2d%2d%2d%2d%2d\n",Max[O].A,Max[0].B,Max[0].QAllocationlOhA,AUocation[0].B,AUocation[0].C,Need[0].A9Need[0].B9Need[0].C9Available.A9Available.B,Available.C);printf("P1%2d%2d%2d%2d%2d%2d%2d%2d%2d\n",Max[1].A,Max[1].B,Max[1].C,AUocation[1].A,Allocation[1].B,Allocation[1]・C,Need[1].A,Need[1].B,Need[1]・C);printf("P2%2d%2d%2d%2d%2d%2d%2d%2d%2d\n",Max[2].A,Max[2].B,Max[2].C,AUocation[2].A,AUocation[2].B,AUocation⑵.CNeed⑵.A,Need⑵.B^Need⑵・C);printf("===============================================================================\n");}〃银行家算法分配voidbanker。{charch;//判断输入的是否是安全状态PrintTable();printf("先检查初始状态是否安全。\n");if(SafeCheck()){printf("系统处于安全状态。\n");printf("安全序列是{P%d,P%df%d}。\n",safe[0],safe[1],safe⑵)；}else{printf("系统处于不安全状态。程序将退出・・.\n");printf("执行完毕。\n");getchar();return;}〃开始分配do{intprocess;RESres;printf("请依次输入请求分配的进程和对三类资源的请求数量(进程编号0.1.2.・・)\n");scanf("%d%d%d%d",&process,&res・A,&res・B,&res・C);if(process<3&&process>=0){if(request(process,&res)){printf("分配成功。\n");PrintTable();printf("安全序列是{P%df%dE%d}。\n",safe[0],safe[1],safe[2]);}else{printf("分配失败。\n");}printf("是否继续分配？(Y/N):");getchar();ch=getchar();}else{printf("输入的进程号0〜2\n");ch='y';}}while(ch=='Y'IIch==,y,);printf("执行完毕。\n");}〃随机分配算法执行boolRandRequest(intprocess,RES*res){//request向量需小于Available向量if(res->A<=Available・A&&res->B<=Available・B&&res->C<=Available.®{〃试探分配ProbeAlloc(process,res);//判断进程是否执行完，执行完释放资源if(Max[process].A<=Allocation[process].A&&Max[process].B<=Allocation[process].B&&Max[process].C<=Allocation[process].C)printf（"\nP%d执行完毕，释放所分配的资源・・.\n",process）;//有则使其执行完成，并将已分配给该进程的资源全部回收Available・A+=Allocation[proeess].A;Available.B+=Allocation[process].B;

Available.C+=Allocation[proeess]・C;AUocation[process].A=0;Allocation[process].B=0;Allocation[process].C=0;Need[process]・A=Max[process].A;Need[process].B=Max[process].B;Need[process].C=Max[process].C;}returntrue;}else{printf（"分配失败。原因：请求大于可利用资源。\n"）;}returnfalse;}〃随机分配voidrandPatch（）{charch;〃判断输入的是否是安全状态PrintTable（）;printf（"先检查初始状态是否安全。\n"）;if（SafeCheckO）{printf（"系统处于安全状态。\n"）;printf（"安全序列是{P%d,P%djP%d}。\n",safe[0]9safe[1]9safe[2]）;}else{printf（"系统处于不安全状态。程序将退出・・.\n"）;printf（"执行完毕。\n"）;getchar();return;}〃开始分配do{intprocess;RESres;printf("请依次输入请求分配的进程和对三类资源的请求数量(进程编号0.1.2.・・)\n");scanf("%d%d%d%d",&process,&res・A,&res・B,&res・C);if(RandRequest(process,&res)){printf("分配成功。\n");PrintTable();if(!SafeCheck()){}printf("系统发生死锁。"getchar();getchar();break;}else{printf（"分配失败。\n"）;}printf("是否继续分配？(Y/N):");getchar();ch=getchar();}while(ch=='Y'IIch=='y');printf("执行完毕。\n");}intmain(){intx;while⑴{printf("=========================\n")；printf("\t\t\t共享资源分配与银行家算法\n");printf("===============================================================================\n");printf("\t\t\t按1•导入配置信息\n");printf("\t\t\t按2•银行家算法\n");printf("\t\t\t按3.随机分配算法\n");printf("\t\t\t按0・退出系统5");printf("===============================================================================\n");printf("您输入的是:");scanf("%d",&x);fflush(stdin);system("cls");printf("===============================================================================\n");printf("\t\t\t共享资源分配与银行家算法")；if(x==2){printf("\t---银行家算法\n");}elseif(x==3){printf("\t---随机分配算法\n");}printf("==========================================================================\n");switch(x){case1:{//加载配置文件loadConfig();//打印资源分配表PrintTable();printf("信息导入完成・・・・.\n");getchar();};break;case2:banker();break;

case3:randPatch（）;break;case0:printf（“退出系统・\n\n”）;return0;break;default:printf（"请输入0~1之间的数字\n"）;}}return0;}/*Config.txt557533229