给我写一个磁盘调度算法，用c++

好的，以下是一个简单的磁盘调度算法的C语言代码：

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

#define MAX_REQUESTS 1000
#define DISK_SIZE 100

int requests[MAX_REQUESTS];
int head_position;

/* 计算距离 */
int distance(int a, int b) {
    if (a > b) {
        return a - b;
    } else {
        return b - a;
    }
}

/* 先来先服务算法 */
void fcfs() {
    int total_distance = 0;

    for (int i = 0; i < MAX_REQUESTS; i++) {
        total_distance += distance(head_position, requests[i]);
        head_position = requests[i];
    }

    printf("FCFS total distance: %d\n", total_distance);
}

/* 最短寻道时间优先算法 */
void sstf() {
    int total_distance = 0;
    int visited[MAX_REQUESTS] = {0};
    int current = head_position;

    for (int i = 0; i < MAX_REQUESTS; i++) {
        int shortest_distance = DISK_SIZE;
        int shortest_index = -1;
        for (int j = 0; j < MAX_REQUESTS; j++) {
            if (!visited[j]) {
                int distance_to_current = distance(current, requests[j]);
                if (distance_to_current < shortest_distance) {
                    shortest_distance = distance_to_current;
                    shortest_index = j;
                }
            }
        }
        visited[shortest_index] = 1;
        total_distance += shortest_distance;
        current = requests[shortest_index];
    }

    printf("SSTF total distance: %d\n", total_distance);
}

/* 扫描算法 */
void scan() {
    int total_distance = 0;
    int visited[MAX_REQUESTS] = {0};
    int current = head_position;
    int direction = 1;

    while (1) {
        int shortest_distance = DISK_SIZE;
        int shortest_index = -1;

        for (int i = 0; i < MAX_REQUESTS; i++) {
            if (!visited[i]) {
                int distance_to_current = distance(current, requests[i]);
                if ((distance_to_current < shortest_distance && direction == 1 && requests[i] >= current) ||
                    (distance_to_current < shortest_distance && direction == -1 && requests[i] <= current)) {
                    shortest_distance = distance_to_current;
                    shortest_index = i;
                }
            }
        }

        if (shortest_index == -1) {
            direction = -direction;
            continue;
        }
        visited[shortest_index] = 1;
        total_distance += shortest_distance;
        current = requests[shortest_index];
        if (total_distance == MAX_REQUESTS) {
            break;
        }
    }

    printf("SCAN total distance: %d\n", total_distance);
}

int main() {
    printf("Please input the requests (up to %d): ", MAX_REQUESTS);
    for (int i = 0; i < MAX_REQUESTS; i++) {
        int request;
        scanf("%d", &request);
        if (request >= 0 && request <= DISK_SIZE) {
            requests[i] = request;
        } else {
            printf("Invalid request! Please input a number between 0 and %d.\n", DISK_SIZE);
            i--;
        }
    }

    printf("Please input the initial head position (between 0 and %d): ", DISK_SIZE);
    scanf("%d", &head_position);
    if (head_position < 0 || head_position > DISK_SIZE) {
        printf("Invalid head position! Please input a number between 0 and %d.\n", DISK_SIZE);
        return 0;
    }

    fcfs();
    sstf();
    scan();

    return 0;
}

这个程序实现了三种不同的磁盘调度算法：先来先服务算法（FCFS）、最短寻道时间优先算法（SSTF）和扫描算法（SCAN）。用户可以输入要处理的磁盘请求数组以及起始磁头位置，程序会分别输出三种算法的总距离（头移动总距离越短越好）。