可变分区管理的3种分配，最先分配算法，最优分配算法，最坏分配算法代码

下面是可变分区管理的三种分配算法的简单代码实现，供参考：

最先分配算法：

struct node {
    int start; // 分区起始地址
    int size; // 分区大小
    int status; // 分区状态，0表示空闲，1表示已分配
    struct node *next; // 指向下一个节点的指针
};

void firstFit(struct node *head, int size) {
    struct node *p = head;
    while (p != NULL) {
        if (p->status == 0 && p->size >= size) {
            p->status = 1;
            printf("已分配分区：起始地址为%d，大小为%d\n", p->start, size);
            if (p->size > size) {
                struct node *node = (struct node*)malloc(sizeof(struct node));
                node->start = p->start + size;
                node->size = p->size - size;
                node->status = 0;
                node->next = p->next;
                p->next = node;
                p->size = size;
            }
            return;
        }
        p = p->next;
    }
    printf("无法分配分区：没有足够的空闲内存\n");
}

最优分配算法：

void bestFit(struct node *head, int size) {
    struct node *p = head;
    struct node *best = NULL;
    while (p != NULL) {
        if (p->status == 0 && p->size >= size) {
            if (best == NULL || p->size < best->size) {
                best = p;
            }
        }
        p = p->next;
    }
    if (best != NULL) {
        best->status = 1;
        printf("已分配分区：起始地址为%d，大小为%d\n", best->start, size);
        if (best->size > size) {
            struct node *node = (struct node*)malloc(sizeof(struct node));
            node->start = best->start + size;
            node->size = best->size - size;
            node->status = 0;
            node->next = best->next;
            best->next = node;
            best->size = size;
        }
    } else {
        printf("无法分配分区：没有足够的空闲内存\n");
    }
}

最坏分配算法：

void worstFit(struct node *head, int size) {
    struct node *p = head;
    struct node *worst = NULL;
    while (p != NULL) {
        if (p->status == 0 && p->size >= size) {
            if (worst == NULL || p->size > worst->size) {
                worst = p;
            }
        }
        p = p->next;
    }
    if (worst != NULL) {
        worst->status = 1;
        printf("已分配分区：起始地址为%d，大小为%d\n", worst->start, size);
        if (worst->size > size) {
            struct node *node = (struct node*)malloc(sizeof(struct node));
            node->start = worst->start + size;
            node->size = worst->size - size;
            node->status = 0;
            node->next = worst->next;
            worst->next = node;
            worst->size = size;
        }
    } else {
        printf("无法分配分区：没有足够的空闲内存\n");
    }
}