lfu页面置换算法c语言实现代码

以下是LFU页面置换算法的C语言实现代码：

#include <stdio.h>
#include <stdlib.h>

#define MAX_SIZE 100

struct lfu_page {
    int page_number;
    int frequency;
    int time;
};

int n, m, page_faults = 0;
lfu_page page_frames[MAX_SIZE];

int find_least_frequent_page() {
    int min_frequency = page_frames[0].frequency;
    int min_time = page_frames[0].time;
    int index = 0;

    for(int i = 1; i < m; i++) {
        if(page_frames[i].frequency < min_frequency) {
            min_frequency = page_frames[i].frequency;
            min_time = page_frames[i].time;
            index = i;
        }
        else if(page_frames[i].frequency == min_frequency && page_frames[i].time < min_time) {
            min_time = page_frames[i].time;
            index = i;
        }
    }

    return index;
}

int find_free_frame() {
    for(int i = 0; i < m; i++) {
        if(page_frames[i].page_number == -1) {
            return i;
        }
    }

    return -1;
}

int find_page_frame(int page_number) {
    for(int i = 0; i < m; i++) {
        if(page_frames[i].page_number == page_number) {
            return i;
        }
    }

    return -1;
}

void print_page_frames() {
    for(int i = 0; i < m; i++) {
        printf("%d ", page_frames[i].page_number);
    }

    printf("\n");
}

void lfu_page_replacement(int pages[]) {
    int time = 0;

    for(int i = 0; i < n; i++) {
        int page_number = pages[i];
        int index = find_page_frame(page_number);

        if(index == -1) {
            index = find_free_frame();

            if(index == -1) {
                index = find_least_frequent_page();
            }

            page_frames[index].page_number = page_number;
            page_frames[index].frequency = 1;
            page_frames[index].time = time;

            page_faults++;
        }
        else {
            page_frames[index].frequency++;
        }

        time++;

        print_page_frames();
    }
}

int main() {
    int pages[MAX_SIZE];

    printf("Enter the number of page frames: ");
    scanf("%d", &m);

    printf("Enter the number of pages: ");
    scanf("%d", &n);

    printf("Enter the page number sequence: ");

    for(int i = 0; i < n; i++) {
        scanf("%d", &pages[i]);
    }

    for(int i = 0; i < m; i++) {
        page_frames[i].page_number = -1;
        page_frames[i].frequency = 0;
        page_frames[i].time = 0;
    }

    lfu_page_replacement(pages);

    printf("Total page faults: %d", page_faults);

    return 0;
}

此代码实现了LFU页面置换算法，可以从命令行输入页面帧数和页面序列，然后输出页面置换的过程和总的页面错误数。