使用java语言实现
时间: 2023-12-10 15:02:56 浏览: 30
以下是Java语言实现页面置换算法的示例代码,使用了FIFO算法:
```
import java.util.Scanner;
public class PageReplacement {
public static void main(String[] args) {
int[] frames, pages;
int numFrames, numPages, faults = 0, i, j, k, flag, victim;
float faultRate;
Scanner sc = new Scanner(System.in);
System.out.print("Enter number of physical frames: ");
numFrames = sc.nextInt();
frames = new int[numFrames];
for(i = 0; i < numFrames; ++i) {
frames[i] = -1;
}
System.out.print("Enter number of page references: ");
numPages = sc.nextInt();
pages = new int[numPages];
System.out.print("Enter page reference string: ");
for(i = 0; i < numPages; ++i) {
pages[i] = sc.nextInt();
}
System.out.println("\nPage Reference String\tPage Frames\tFaults");
for(i = 0; i < numPages; ++i) {
System.out.print(pages[i] + "\t\t\t");
flag = 0;
for(k = 0; k < numFrames; ++k) {
if(frames[k] == pages[i]) {
flag = 1;
break;
}
}
if(flag == 0) {
++faults;
if(i < numFrames) {
frames[i] = pages[i];
}
else {
victim = 0;
for(j = 1; j < numFrames; ++j) {
if(frames[j] == pages[i]) {
victim = j;
break;
}
if(frames[j] < frames[victim]) {
victim = j;
}
}
frames[victim] = pages[i];
}
}
for(k = 0; k < numFrames; ++k) {
System.out.print(frames[k] + " ");
}
System.out.println("\t\t" + faults);
}
faultRate = (float)faults / (float)numPages;
System.out.println("\nTotal Page Faults: " + faults);
System.out.println("Total Page Calls: " + numPages);
System.out.printf("Page Fault Rate: %.2f%%\n", faultRate * 100);
sc.close();
}
}
```
该示例使用了与前面的示例相同的逻辑,但使用了Java语言实现。它从用户输入中获取物理页框数和页面走向,然后动态分配帧数组和页面数组。接下来,每次循环检查页面是否已经存在于帧数组中。如果页面不存在,则将缺页次数加1,并检查帧数组是否已满,如果帧数组未满,则将页面添加到下一个空闲帧中。如果帧数组已满,则使用最久未被使用的页面替换。最后,计算缺页中断率并输出。