c语言实现+lru+替换算法

LRU（Least Recently Used）是一种页面置换算法，它会将最近最少使用的页面替换出去。下面是C语言实现LRU替换算法的示例代码：

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

int main()
{
    int frames, pages, counter = 0, time[10], flag1, flag2, i, j, pos, faults = 0;
    int frame[10], arr[30];
    printf("Enter number of frames: ");    scanf("%d", &frames);

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

    printf("Enter reference string: ");

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

    for(i = 0; i < frames; ++i){
        frame[i] = -1;
    }

    for(i = 0; i < pages; ++i){
        flag1 = flag2 = 0;

        for(j = 0; j < frames; ++j){
            if(frame[j] == arr[i]){
                counter++;
                time[j] = counter;
                flag1 = flag2 = 1;
                break;
            }
        }

        if(flag1 == 0){
            for(j = 0; j < frames; ++j){
                if(frame[j] == -1){
                    counter++;
                    faults++;
                    frame[j] = arr[i];
                    time[j] = counter;
                    flag2 = 1;
                    break;
                }
            }    
        }

        if(flag2 == 0){
            pos = findLRU(time, frames);
            counter++;
            faults++;
            frame[pos] = arr[i];
            time[pos] = counter;
        }

        printf("\n");

        for(j = 0; j < frames; ++j){
            printf("%d\t", frame[j]);
        }
    }

    printf("\n\nTotal Page Faults = %d", faults);

    return 0;
}

int findLRU(int time[], int n){
    int i, minimum = time[0], pos = 0;

    for(i = 1; i < n; ++i){
        if(time[i] < minimum){
            minimum = time[i];
            pos = i;
        }
    }

    return pos;
}