c语言实现三种页面置换算法
时间: 2023-08-13 22:05:31 浏览: 57
好的,以下是三种常见的页面置换算法的C语言实现:
1. 先进先出(FIFO)算法
```c
#include <stdio.h>
#define MAX_SIZE 100
int main() {
int pageFaults = 0, pointer = 0, n, m;
int frames[MAX_SIZE], pages[MAX_SIZE];
printf("Enter number of frames: ");
scanf("%d", &n);
printf("Enter number of pages: ");
scanf("%d", &m);
printf("Enter reference string: ");
for (int i = 0; i < m; i++) {
scanf("%d", &pages[i]);
}
for (int i = 0; i < n; i++) {
frames[i] = -1;
}
for (int i = 0; i < m; i++) {
int page = pages[i];
int found = 0;
for (int j = 0; j < n; j++) {
if (frames[j] == page) {
found = 1;
break;
}
}
if (!found) {
frames[pointer] = page;
pointer = (pointer + 1) % n;
pageFaults++;
}
}
printf("Number of page faults: %d\n", pageFaults);
return 0;
}
```
2. 最近最久未使用(LRU)算法
```c
#include <stdio.h>
#define MAX_SIZE 100
int main() {
int pageFaults = 0, n, m, pointer = 0;
int frames[MAX_SIZE], pages[MAX_SIZE], time[MAX_SIZE];
printf("Enter number of frames: ");
scanf("%d", &n);
printf("Enter number of pages: ");
scanf("%d", &m);
printf("Enter reference string: ");
for (int i = 0; i < m; i++) {
scanf("%d", &pages[i]);
}
for (int i = 0; i < n; i++) {
frames[i] = -1;
time[i] = 0;
}
for (int i = 0; i < m; i++) {
int page = pages[i];
int found = 0;
for (int j = 0; j < n; j++) {
if (frames[j] == page) {
found = 1;
time[j] = i + 1;
break;
}
}
if (!found) {
int oldest = 0;
for (int j = 1; j < n; j++) {
if (time[j] < time[oldest]) {
oldest = j;
}
}
frames[oldest] = page;
time[oldest] = i + 1;
pageFaults++;
}
}
printf("Number of page faults: %d\n", pageFaults);
return 0;
}
```
3. 时钟(Clock)算法
```c
#include <stdio.h>
#define MAX_SIZE 100
int main() {
int pageFaults = 0, pointer = 0, n, m;
int frames[MAX_SIZE], pages[MAX_SIZE], reference[MAX_SIZE];
printf("Enter number of frames: ");
scanf("%d", &n);
printf("Enter number of pages: ");
scanf("%d", &m);
printf("Enter reference string: ");
for (int i = 0; i < m; i++) {
scanf("%d", &pages[i]);
}
for (int i = 0; i < n; i++) {
frames[i] = -1;
reference[i] = 0;
}
for (int i = 0; i < m; i++) {
int page = pages[i];
int found = 0;
for (int j = 0; j < n; j++) {
if (frames[j] == page) {
found = 1;
reference[j] = 1;
break;
}
}
if (!found) {
while (reference[pointer]) {
reference[pointer] = 0;
pointer = (pointer + 1) % n;
}
frames[pointer] = page;
reference[pointer] = 1;
pointer = (pointer + 1) % n;
pageFaults++;
}
}
printf("Number of page faults: %d\n", pageFaults);
return 0;
}
```
以上三种算法的实现均为基本版,没有做过多的优化处理。