c语言实现三种页面置换算法

好的，这里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

#include <stdio.h>
#define SIZE 4

int main()
{
    int frames[SIZE], pages[SIZE], faults = 0, pointer = 0;
    int n, m, flag, i, j;

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

    printf("Enter reference string: ");
    for (i = 0; i < n; i++)
        scanf("%d", &pages[i]);

    for (i = 0; i < SIZE; i++)
        frames[i] = -1;

    for (i = 0; i < n; i++)
    {
        flag = 0;
        for (j = 0; j < SIZE; j++)
        {
            if (frames[j] == pages[i])
            {
                flag = 1;
                break;
            }
        }
        if (!flag)
        {
            frames[pointer] = pages[i];
            pointer = (pointer + 1) % SIZE;
            faults++;
        }
        printf("\n");
        for (j = 0; j < SIZE; j++)
            printf("%d\t", frames[j]);
    }
    printf("\nTotal Page Faults: %d", faults);

    return 0;
}

2. 最近最少使用（LRU）算法

#include <stdio.h>
#define SIZE 4

int main()
{
    int frames[SIZE], pages[SIZE], faults = 0, counter = 0;
    int n, m, flag, i, j, k, min;

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

    printf("Enter reference string: ");
    for (i = 0; i < n; i++)
        scanf("%d", &pages[i]);

    for (i = 0; i < SIZE; i++)
        frames[i] = -1;

    for (i = 0; i < n; i++)
    {
        flag = 0;
        for (j = 0; j < SIZE; j++)
        {
            if (frames[j] == pages[i])
            {
                flag = 1;
                counter++;
                break;
            }
        }
        if (!flag)
        {
            min = 9999;
            for (j = 0; j < SIZE; j++)
            {
                flag = 0;
                for (k = i - 1; k >= 0; k--)
                {
                    if (frames[j] == pages[k])
                    {
                        flag = 1;
                        break;
                    }
                }
                if (!flag && min > k)
                {
                    min = k;
                    counter = j;
                }
            }
            frames[counter] = pages[i];
            faults++;
        }
        printf("\n");
        for (j = 0; j < SIZE; j++)
            printf("%d\t", frames[j]);
    }
    printf("\nTotal Page Faults: %d", faults);

    return 0;
}

3. 时钟（Clock）算法

#include <stdio.h>
#define SIZE 4

int main()
{
    int frames[SIZE], pages[SIZE], faults = 0, pointer = 0;
    int n, m, flag, i, j, used[SIZE] = {0};

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

    printf("Enter reference string: ");
    for (i = 0; i < n; i++)
        scanf("%d", &pages[i]);

    for (i = 0; i < SIZE; i++)
        frames[i] = -1;

    for (i = 0; i < n; i++)
    {
        flag = 0;
        for (j = 0; j < SIZE; j++)
        {
            if (frames[j] == pages[i])
            {
                flag = 1;
                used[j] = 1;
                break;
            }
        }
        if (!flag)
        {
            while (used[pointer])
            {
                used[pointer] = 0;
                pointer = (pointer + 1) % SIZE;
            }
            frames[pointer] = pages[i];
            used[pointer] = 1;
            pointer = (pointer + 1) % SIZE;
            faults++;
        }
        printf("\n");
        for (j = 0; j < SIZE; j++)
            printf("%d\t", frames[j]);
    }
    printf("\nTotal Page Faults: %d", faults);

    return 0;
}

希望能够帮助到你！