银行家算法实验报告.doc

银行家算法实验报告实验目的：了解和掌握银行家算法，进一步熟悉进程和如何避免死锁。实验内容：1、主要程序结构(a)resource allocation algorithm nest.allocl*+request*nest.claiml* error /如果要求的资源量+占有的资源总的资源需求量requestinest.availablei结束 N Ynest.allocl*=nest.allocl*+request*;nest.vailable*=nest.available*-request*; NSafe(nest)=truesuspend N t=true Y /t=true可以carry out allocation结束(b) test for safety algorithm 注：- 中的内容为未具体写明但说明其功能的程序段bool safe(struct state new )bool possible = true,found=false;process restn;/正在执行的进程号int p=n;/ 正在执行的进程数量int currentavailm;/可用资源的一个副本-为rest和currentavail赋值-while(possible=true&p0)int g=0; -寻找可以执行完成的进程-if(found=true)int c=0; -假设可以执行完的进程以完成，及currentavail*=currentavail*+new.allocg*;-restg = -1;-p;found =false;elsepossible=false;return possible;2、实验步骤1）设计结构体#ifndef STATE_H_#define m 3#define n 5struct stateint resourcem;int availablem;int claimnm;int allocnm; ;#define STATE_H_#endif /* STATE_H_ */2）设计实现程序的结构的具体程序Safe算法的具体代码bool safe(struct state new )bool possible = true,found=false;process restn; /正在执行的进程号int f=0,p=n;/ 正在执行的进程数量dorestf=f;+f;while(fn);int currentavailm; /可用资源的一个副本int i=0;docurrentavaili=new.availablei;+i;while(i0)int g=0;/*-寻找可以执行完成的进程-*/while(gn)int h = 0; /*while(hm)if(new.claimgh-new.allocgh)=currentavailh&restg!=(-1)if(h=m-1)found=true;+h;if(found=true)break;+g;/*-*/if(found=true)int c=0;while(cm)currentavailc=currentavailc+new.allocgc;c+;restg = -1;-p;found =false;elsepossible=false;return possible;实验代码：/* = Name : pre.c Author : Version : Copyright : Your copyright notice Description : Hello World in C, Ansi-style = */#include #include #includestate.h#define bool int#define process int#define false 0#define true 1int main(void) bool alloc(int,int,struct state );struct state sta1=10,5,7,3,3,2,7,5,3,3,2,2,9,0,2,2,2,2,4,3,3,0,1,0,2,0,0,3,0,2,2,1,1,0,0,2;int requestm;int k=0;while(k=0)puts(输入要改变资源的进程号);scanf(%d,&k);puts(输入要改变的资源);int i =0;while(im)scanf(%d,&requesti);i+;if(alloc(k,request,sta1)=true)i=0;puts(输出个进程占用的资源);while(in)int j=0;printf(%d ,i);while(jm)if(i=k)sta1.allockj=requestj+sta1.allockj;sta1.availablej=sta1.availablej-requestj;printf(%d ,sta1.allocij);j+;printf(n);+i;puts(!银行家算法!);return 0;bool alloc(int l,int requestm,struct state nest)bool safe(struct state news);bool t = false;int i=0;while(inest.claimli)puts(!resource request error!);return false;else if(requestinest.availablei)puts(suspend process);return false;elseif(i=m-1)int f=0;while(fm)nest.alloclf=nest.alloclf+requestf;nest.availablef=nest.availablef-requestf;f+;if(safe(nest)=true)t=true;elseputs( no safe suspend process);t=false;i+;return t;bool safe(struct state new )bool possible = true,found=false;process restn;int f=0,p=n;dorestf=f;+f;while(fn);int currentavailm;int i=0;docurrentavaili=new.availablei;+i;while(i0)int g=0;while(gn)int h = 0;while(hm&(new.claimgh-new.allocgh)=currentavailh&restg!=(-1)if(h=m-1)found=true;+h;if(found=t