用c语言编写可变式分区管理代码，要包括最佳适应算法，最先适应算法和最差适应算法

以下是一个简单的可变式分区管理代码，包括最佳适应算法，最先适应算法和最差适应算法：

#include <stdio.h>

#define MAX_MEM_SIZE 1024

typedef struct {
    int start;
    int end;
    int size;
    int status;   // 0 - free, 1 - allocated
} Partition;

Partition partitions[MAX_MEM_SIZE];
int numOfPartitions = 0;

// 初始化分区表
void initializePartitions() {
    Partition p = {0, MAX_MEM_SIZE - 1, MAX_MEM_SIZE, 0};
    partitions[numOfPartitions++] = p;
}

// 打印分区表
void printPartitions() {
    printf("Partition Table:\n");
    printf("Start\tEnd\tSize\tStatus\n");
    for (int i = 0; i < numOfPartitions; i++) {
        printf("%d\t%d\t%d\t%s\n", partitions[i].start, partitions[i].end, partitions[i].size, partitions[i].status == 0 ? "Free" : "Allocated");
    }
    printf("\n");
}

// 最佳适应算法
int bestFit(int size) {
    int index = -1;
    int minSize = MAX_MEM_SIZE + 1;
    for (int i = 0; i < numOfPartitions; i++) {
        if (partitions[i].status == 0 && partitions[i].size >= size && partitions[i].size < minSize) {
            index = i;
            minSize = partitions[i].size;
        }
    }
    return index;
}

// 最先适应算法
int firstFit(int size) {
    for (int i = 0; i < numOfPartitions; i++) {
        if (partitions[i].status == 0 && partitions[i].size >= size) {
            return i;
        }
    }
    return -1;
}

// 最差适应算法
int worstFit(int size) {
    int index = -1;
    int maxSize = -1;
    for (int i = 0; i < numOfPartitions; i++) {
        if (partitions[i].status == 0 && partitions[i].size >= size && partitions[i].size > maxSize) {
            index = i;
            maxSize = partitions[i].size;
        }
    }
    return index;
}

// 分配内存
void allocateMemory(int size, int algorithm) {
    int index = -1;
    switch (algorithm) {
        case 1:  // 最佳适应算法
            index = bestFit(size);
            break;
        case 2:  // 最先适应算法
            index = firstFit(size);
            break;
        case 3:  // 最差适应算法
            index = worstFit(size);
            break;
        default:
            printf("Invalid algorithm!\n");
            return;
    }
    if (index != -1) {
        Partition p = partitions[index];
        p.status = 1;
        p.size = size;
        partitions[index] = p;
        if (p.start + size <= p.end) {
            Partition newPartition = {p.start + size, p.end, p.end - (p.start + size) + 1, 0};
            partitions[numOfPartitions++] = newPartition;
        }
        printf("Memory allocated successfully!\n");
    } else {
        printf("Memory allocation failed!\n");
    }
}

// 释放内存
void freeMemory(int start) {
    for (int i = 0; i < numOfPartitions; i++) {
        Partition p = partitions[i];
        if (p.start == start && p.status == 1) {
            p.status = 0;
            partitions[i] = p;
            printf("Memory freed successfully!\n");
            return;
        }
    }
    printf("Memory free failed!\n");
}

int main() {
    initializePartitions();
    int choice = 0;
    do {
        printf("1. Print partition table\n");
        printf("2. Allocate memory\n");
        printf("3. Free memory\n");
        printf("4. Exit\n");
        printf("Enter your choice: ");
        scanf("%d", &choice);
        switch (choice) {
            case 1:
                printPartitions();
                break;
            case 2:
                printf("Enter memory size to allocate: ");
                int size;
                scanf("%d", &size);
                printf("Enter algorithm (1 - best fit, 2 - first fit, 3 - worst fit): ");
                int algorithm;
                scanf("%d", &algorithm);
                allocateMemory(size, algorithm);
                break;
            case 3:
                printf("Enter memory start address to free: ");
                int start;
                scanf("%d", &start);
                freeMemory(start);
                break;
            case 4:
                printf("Exiting program.\n");
                break;
            default:
                printf("Invalid choice!\n");
                break;
        }
    } while (choice != 4);

    return 0;
}