编写页面置换算法实现的java程序,要求输出显示页引用字符串、分配的内存块数、页面调度算法、页面调度过程、缺页次数、缺页率。要求实现页面置换算法FIFO 和 LRU。
时间: 2023-11-27 15:02:52 浏览: 107
以下是FIFO页面置换算法的Java代码实现:
```java
import java.util.*;
public class FIFOPageReplacement {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
System.out.print("请输入页引用字符串(用空格隔开):");
String s = sc.nextLine();
String[] pages = s.split(" ");
System.out.print("请输入分配的内存块数:");
int capacity = sc.nextInt();
sc.close();
List<Integer> memory = new ArrayList<>();
int pageFaults = 0;
int pointer = 0;
System.out.println("\nFIFO页面调度算法:");
for (String page : pages) {
int num = Integer.parseInt(page);
if (memory.size() < capacity) {
if (!memory.contains(num)) {
memory.add(num);
pageFaults++;
}
} else {
if (!memory.contains(num)) {
memory.set(pointer, num);
pointer++;
if (pointer == capacity) {
pointer = 0;
}
pageFaults++;
}
}
System.out.println("调度过程: " + memory);
}
double pageFaultRate = (double) pageFaults / pages.length;
System.out.println("\n缺页次数: " + pageFaults);
System.out.println("缺页率: " + pageFaultRate);
}
}
```
以下是LRU页面置换算法的Java代码实现:
```java
import java.util.*;
public class LRUPageReplacement {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
System.out.print("请输入页引用字符串(用空格隔开):");
String s = sc.nextLine();
String[] pages = s.split(" ");
System.out.print("请输入分配的内存块数:");
int capacity = sc.nextInt();
sc.close();
List<Integer> memory = new ArrayList<>();
Map<Integer, Integer> indexes = new HashMap<>();
int pageFaults = 0;
System.out.println("\nLRU页面调度算法:");
for (String page : pages) {
int num = Integer.parseInt(page);
if (memory.size() < capacity) {
if (!memory.contains(num)) {
memory.add(num);
pageFaults++;
}
indexes.put(num, memory.size() - 1);
} else {
if (!memory.contains(num)) {
int leastUsedIndex = Integer.MAX_VALUE;
int leastUsedPage = -1;
for (Map.Entry<Integer, Integer> entry : indexes.entrySet()) {
if (entry.getValue() < leastUsedIndex) {
leastUsedIndex = entry.getValue();
leastUsedPage = entry.getKey();
}
}
memory.set(leastUsedIndex, num);
indexes.remove(leastUsedPage);
indexes.put(num, leastUsedIndex);
pageFaults++;
} else {
indexes.put(num, memory.indexOf(num));
}
}
System.out.println("调度过程: " + memory);
}
double pageFaultRate = (double) pageFaults / pages.length;
System.out.println("\n缺页次数: " + pageFaults);
System.out.println("缺页率: " + pageFaultRate);
}
}
```
参考以上代码实现,你可以编写页面置换算法实现的Java程序,并获得所需的输出。
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