页面置换算法c语言代码

以下是一个简单的页面置换算法（LRU）的C语言代码实现：

#include <stdio.h>

#define MAX_FRAMES 10

int main() {
    int reference_string[20], frames[MAX_FRAMES], temp[MAX_FRAMES];
    int num_pages, num_frames, page_faults = 0, m, n, position, k, l, flag;
    int buffer[MAX_FRAMES][MAX_FRAMES];

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

    printf("Enter the reference string: ");
    for(m = 0; m < num_pages; m++)
        scanf("%d", &reference_string[m]);

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

    for(m = 0; m < num_frames; m++)
        frames[m] = -1;

    for(m = 0; m < num_pages; m++) {
        flag = 0;
        for(n = 0; n < num_frames; n++) {
            if(frames[n] == reference_string[m]) {
                flag = 1;
                break;
            }
        }

        if(flag == 0) {
            for(n = 0; n < num_frames; n++)
                temp[n] = 0;

            for(k = m - 1, l = 1; l <= num_frames - 1; l++, k--) {
                position = -1;
                for(n = 0; n < num_frames; n++) {
                    if(frames[n] == reference_string[k]) {
                        position = n;
                        break;
                    }
                }

                if(position != -1)
                    temp[position] = 1;
            }

            for(n = 0; n < num_frames; n++) {
                if(temp[n] == 0) {
                    frames[n] = reference_string[m];
                    buffer[n][m] = frames[n];
                    page_faults++;
                    break;
                }
            }
        }
        else {
            for(n = 0; n < num_frames; n++)
                buffer[n][m] = frames[n];
        }
    }

    printf("\nPage Faults: %d\n", page_faults);

    printf("\nPage Frames:\n");
    for(m = 0; m < num_frames; m++) {
        for(n = 0; n < num_pages; n++) {
            if(buffer[m][n] == -1)
                printf("  ");
            else
                printf("%d ", buffer[m][n]);
        }
        printf("\n");
    }

    return 0;
}

该代码实现了一个简单的页面置换算法，其中使用了一个双重循环来查找最近最少使用的页面，并使用一个二维数组来保存每个页面在每个时刻的状态。