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package cn.hncu.mytext;
import java.util.Scanner;
public class BankerOfAlgorithm {//BankerOfAlgorithm 银行家算法
int Max[][];
int Allocation[][];
int Need[][];
int Available[];
int Work[];
String name[];
int temp[];
int S = 100, P = 100;
int safequeue[];
int Request[];
Scanner sc;
public BankerOfAlgorithm() {
int text_temp = 100;
int Max[][] = new int[text_temp][text_temp];
int Allocation[][] = new int[text_temp][text_temp];
int Need[][] = new int[text_temp][text_temp];
int Available[] = new int[text_temp];
int Work[] = new int[text_temp];
String name[] = new String[text_temp];
int temp[] = new int[text_temp];
int S = 100, P = 100;
int safequeue[] = new int[text_temp];
int Request[] = new int[text_temp];
}
public void Showdata() {
int i, j, k, l;
System.out.println("\t资源分配情况\n");
System.out.println("\tMax\t已分配\tNeed");
System.out.print("\t");
for (j = 0; j < 3; j++) {
for (i = 0; i < S; i++) {
System.out.print(name[i] + " ");
}
System.out.print("\t");
}
System.out.println();
for (i = 0; i < P; i++) {
System.out.print(i+"\t");
for (j = 0; j < S; j++) {
System.out.print(Max[i][j] + " ");
}
System.out.print("\t");
for (k = 0; k < S; k++) {
System.out.print(Allocation[i][k] + " ");
}
System.out.print("\t");
for (l = 0; l < S; l++) {
System.out.print(Need[i][l] + " ");
}
System.out.println();
}
System.out.println("\nAvailable");
for (i = 0; i < S; i++) {
System.out.print(name[i] + " ");
}
System.out.println();
for (i = 0; i < S; i++) {
System.out.print(Available[i] + " ");
}
System.out.println();
}
public int Judgesafe() {
int[][] tempwork = new int[100][100];
int i, x, k = 0, m, apply;
int[] Finish = new int[100];
int[] temp = new int[100];
int j;
int flag = 0;
Work = new int[100];
for (i = 0; i < S; i++) {
Work[i] = Available[i];
}
for (i = 0; i < P; i++) {
apply = 0;
for (j = 0; j < S; j++) {
if (Finish[i] == 0 && Need[i][j] <= Work[j]) {
apply++;
if (apply == S) {
for (m = 0; m < S; m++) {
tempwork[i][m] = Work[m];
Work[m] = Work[m] + Allocation[i][m];
}
Finish[i] = 1;
temp[k] = i;
i = -1;
k++;
flag++;
}
}
}
}
for (i = 0; i < P; i++) {
if (Finish[i] == 0) {
System.out.println("系统不安全");
return -1;
}
}
System.out.println("系统是安全的");
System.out.print("分配的序列:");
for (i = 0; i < P; i++) {
System.out.print(temp[i]);
if (i < P - 1) {
System.out.print("->");
}
}
System.out.println();
return 0;
}
public void Changedata(int flag) {
for (int i = 0; i < S; i++) {
Available[i] = Available[i] - Request[i];
Allocation[flag][i] = Allocation[flag][i] + Request[i];
Need[flag][i] = Need[flag][i] - Request[i];
}
}
public void Share() {
sc = new Scanner(System.in);
int i, flag;
char ch = 'Y';
System.out.println("输入请求资源的进程：");
flag = sc.nextInt();
Request = new int[100];
if (flag >= P) {
System.out.println("此进程不存在!");
} else {
System.out.println("输入此进程对各个资源的请求数量：");
for (i = 0; i < S; i++) {
Request[i] = sc.nextInt();
}
for (i = 0; i < S; i++) {
if (Request[i] > Need[flag][i]) {
System.out.println("进程" + flag + "申请的资源大于它所需要的资源!");
System.out.println("分配不合理不予分配!");
ch = 'N';
break;
} else if (Request[i] > Available[i]) {
System.out.println("进程" + flag + "申请的资源大于可利用的资源。");
System.out.println("分配不合理，不予分配!");
ch = 'N';
break;
}
}
if (ch == 'Y') {
Changedata(flag);
if (Judgesafe() == -1) {
System.out.println("进程" + flag + "申请资源后，系统进入死锁状态，分配失败!");
for (int j = 0; j < S; j++) {
Available[j] = Available[j] + Request[j];
Allocation[flag][j] = Allocation[flag][j] - Request[j];
Need[flag][j] = Need[flag][j] + Request[j];
}
}
}
}
}
public static void main(String[] args) {
BankerOfAlgorithm mytext = new BankerOfAlgorithm();
Scanner sc = new Scanner(System.in);
int i, j, p, s, number;
String choice, tempstring;
System.out.println("\t\t操作系统实验六");
System.out.println("输入资源种类：");
s = sc.nextInt();
mytext.S = s;
System.out.println("输入资源的名称和数量：");
mytext.name = new String[100];
mytext.Available = new int[100];
for (i = 0; i < s; i++) {
tempstring = sc.next();
number = sc.nextInt();
mytext.name[i] = tempstring;
mytext.Available[i] = number;
}
System.out.println("输入进程的数量：");
p = sc.nextInt();
mytext.P = p;
System.out.println("输入各进程资源最大需求量：");
mytext.Max = new int[100][100];
for (i = 0; i < p; i++) {
for (j = 0; j < s; j++) {
mytext.Max[i][j] = sc.nextInt();
}
}
System.out.println("输入各进程资源已分配量：");
mytext.Allocation = new int[100][100];
for (i = 0; i < p; i++) {
for (j = 0; j < s; j++) {
mytext.Allocation[i][j] = sc.nextInt();
mytext.Available[j] = mytext.Available[j]
- mytext.Allocation[i][j];
}
}
mytext.Need = new int[100][100];
for (i = 0; i < p; i++) {
for (j = 0; j < s; j++) {
mytext.Need[i][j] = mytext.Max[i][j] - mytext.Allocation[i][j];
}
}
mytext.Showdata();
mytext.Judgesafe();
while (true) {
System.out.println("是否分配资源(n是关闭)：");
choice = sc.next();
char choice_char = choice.charAt(0);
switch (choice_char) {
case 'n':
System.exit(0);
default:
mytext.Share();
break;
}
mytext.Showdata();
mytext.Judgesafe();
}
}
}
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原文地址：http://blog.csdn.net/hncu1306602liuqiang/article/details/46390381
