操作系统实验报告--银行家算法.doc

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1、 操作系统实验报告 二一：实验标题： 实现死锁避免算法：银行家算法。二：实验环境：操作系统：windows7编译器：Visual Studio 2010三：设计方案： 1.实验目的 通过程序模拟银行家算法，理解如何应用银行家算法避免死锁。 2.实验手段 直接在C源程序定义整形进程数量、资源种类；用2维数组表示最大需求、已分配的资源。从文件获取相关数量。 3.验证方式 检验当前资源是否有安全序列，是的话输出安全序列。四：实验代码：#include #include #define P_num 5#define R_num 3int AllocationP_numR_num,AvaliableR_

2、num,MaxP_numR_num;int NeedP_numR_num;int compare(int *a,int *b,int n)int i;for(i = 0;i n;i +)if(ai bi)return 0;return 1;void add(int *a,int *b,int n)int i;for(i = 0;i n;i+)ai += bi;void substract(int *a,int *b,int n)int i;for(i = 0;i n;i+)ai -= bi;void assign(int *a,int *b,int n)int i;for(i = 0;i n;

3、i +)ai = bi;void input()FILE *fp;int i,j;if(fp = fopen(banker.txt,r) = 0)printf(cannot open the file);exit(0);for(i = 0;i P_num; +i) for(j = 0;j R_num; +j)fscanf(fp,%d,&Allocationij);for(i = 0;i P_num; +i) for(j = 0;j R_num; +j)fscanf(fp,%d,&Maxij);for(j = 0;j R_num; +j) fscanf(fp,%d,&Avaliablej);fc

4、lose(fp);for(i = 0;i P_num; +i) for(j = 0;j R_num; +j)Needij = Maxij - Allocationij;int issafe(int *sp)int i;int count = 0;int n = 0;int workR_num,finishP_num;assign(work,Avaliable,R_num);for(i = 0;i P_num;i +)finishi = 0;n = P_num;while(n -)for(i = 0;i = P_num)return 1;return 0;int request(int pid,

5、int *r,int n)int i;int spP_num;if(compare(Needpid,r,n) = 1 & compare(Avaliable,r,n) = 1)substract(Avaliable,r,n);add(Allocationpid,r,n);substract(Needpid,r,n);if(issafe(sp)printf(Security Path:nt);for(i = 0;i P_num;i +)printf(p%d ,spi);printf(n);return 1;elseadd(Avaliable,r,n);substract(Allocationpi

6、d,r,n);add(Needpid,r,n);printf(no Security Parh on this requestn);return 0;elseprintf(no Security Parh on this requestn);return 0;void main()int id,i;int rR_num,spP_num;input();if(issafe(sp)printf(Security Path:nt);for(i = 0;i P_num;i +)printf(p%d ,spi);printf(n);elseprintf(failedn);printf(input the

7、 new requests id:);scanf(%d,&id);printf(input the new request:);for(i = 0;i R_num;+ i)scanf(%d,&ri);request(id,r,R_num);banker.txt文件内容：0 1 02 0 03 0 22 1 10 0 27 5 33 2 29 0 22 2 24 3 33 3 2所得结果：Security Path: P1 p3 p4 p0 p2Intput the new requests id:0Input the new request:0 2 0Security Path:p3 p1 p2 p0 p4问题和想法：