java版本银行家算法

import java.util.Scanner;
public class yinhangjia
{
int available[] = new int[]{3,3,2};
int max[][] = new int[][]{{7,5,3},{3,2,2},{9,0,2},{2,2,2},{4,3,3}};
int allocation[][] = new int[][]{{0,1,0},{2,0,0},{3,0,2},{2,1,1},{0,0,2}};
int need[][] = new int[][]{{7,4,3},{1,2,2},{6,0,0},{0,1,1},{4,3,1}};
void showData()
{
System.out.println("进程号      Max   Allocation Need   ");
System.out.println("     A  B  C  A  B  C  A  B  C");
for(int i = 0;i<5;i++)
{
System.out.print(i+"    ");
for(int m = 0;m<3;m++) System.out.print(max[i][m]+"  ");
for(int m = 0;m<3;m++) System.out.print(allocation[i][m]+"  ");
for(int m = 0;m<3;m++) System.out.print(need[i][m]+"  ");
System.out.println();
}
}
boolean change(int inRequestNum,int inRequest[])
{
int requestNum = inRequestNum;
int request[] = inRequest;

if(!(request[0]<=need[requestNum][0]&&request[1]<=need[requestNum][1]&&request[2]<=need[requestNum][2]))
{
System.out.println("请求的资源数超过了所需要的最大值");
return false;
}
if((request[0]<=available[0]&&request[1]<=available[1]&&request[2]<=available[2])==false)
{
System.out.println("尚无足够资源分配");
return false;
}

for(int i = 0;i<3;i++)
{
available[i] = available[i]-request[i];
allocation[requestNum][i] = allocation[requestNum][i] + request[i];
need[requestNum][i] = need[requestNum][i] - request[i];
}

boolean flag = checkSafe(available[0],available[1],available[2]);//进行安全性检查并返回是否安全
if(flag==true)
{
System.out.println("能够安全分配");
return true;
}
else
{
System.out.println("不能够安全分配");
for(int i = 0;i<3;i++)
{
available[i] = available[i]+request[i];
allocation[requestNum][i] = allocation[requestNum][i] - request[i];
need[requestNum][i] = need[requestNum][i] + request[i];
}
return false;
}
}

boolean checkSafe(int a,int b,int c)//安全性检查
{
int work[] = new int[3];
work[0] = a;
work[1] = b;
work[2] = c;
int i=0;
boolean finish[] =  new boolean[5];
/*while(i<5)
{
if(finish[i]==false&&need[i][0]<=work[0]&&need[i][1]<=work[1]&&need[i][2]<=work[2])
{
System.out.println("分配成功的是"+i);
for(int m = 0;m<3;m++)
work[m] =work[m] + allocation[i][m];
finish[i] = true;
i=0;
}
else
i++;
}*/
boolean x=true;
int n=0;
int nn=0;
while(x){
for(int j=0;j<5;j++){
if(finish[j]==false&&need[j][0]<=work[0]&&need[j][1]<=work[1]&&need[j][2]<=work[2])
{
System.out.println("分配成功的是"+j);
for(int m = 0;m<3;m++)
work[m] =work[m] + allocation[j][m];
finish[j] = true;
n++;
}
}
if(n==nn){
break;
}
nn=n;
}
for(i=0;i<5;i++)
{
if(finish[i]==false)
return false;
}
return true;
}

public static void main(String[] args)
{
yinhangjia bank = new yinhangjia();
bank.showData();
int request[] =new int[3];
int requestNum;
String source[] = new String[]{"A","B","C"};
Scanner s = new Scanner(System.in);
String choice = new String();
while(true)//循环进行分配
{
System.out.println("请输入要请求的进程号（0--4）：");
requestNum = s.nextInt();
System.out.print("请输入请求的资源数目");
for(int i = 0;i<3;i++)
{
System.out.println(source[i]+"资源的数目：");
request[i] = s.nextInt();
}
bank.change(requestNum, request);
//bank.showData();
System.out.println("是否再请求分配(y/n)");
choice = s.next();
if(choice.equals("n"))
break;
}
}
}