C语言中动态数组怎么实现C语言柔性数组的应用场景分析

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

typedef struct {
    int size;       // 当前数组容量
    int capacity;   // 最大容量
    int *data;      // 指向数组的指针
} DynamicArray;

// 初始化动态数组
DynamicArray* initDynamicArray(int initialCapacity) {
    DynamicArray* arr = (DynamicArray*)malloc(sizeof(DynamicArray));
    if (arr == NULL) {
        return NULL; // 内存分配失败
    }
    arr->data = (int*)malloc(initialCapacity * sizeof(int));
    if (arr->data == NULL) {
        free(arr);
        return NULL; // 内存分配失败
    }
    arr->size = 0;
    arr->capacity = initialCapacity;
    return arr;
}

// 向动态数组添加元素
void addElement(DynamicArray* arr, int element) {
    if (arr->size == arr->capacity) {
        // 数组已满，需要扩容
        int newCapacity = arr->capacity * 2;
        int* newData = (int*)realloc(arr->data, newCapacity * sizeof(int));
        if (newData == NULL) {
            // 扩容失败，处理错误
            printf("内存扩容失败！\n");
            return;
        }
        arr->data = newData;
        arr->capacity = newCapacity;
    }
    arr->data[arr->size] = element;
    arr->size++;
}

// 释放动态数组内存
void freeDynamicArray(DynamicArray* arr) {
    free(arr->data);
    free(arr);
}

int main() {
    DynamicArray* myArray = initDynamicArray(2);
    if (myArray == NULL) {
        printf("动态数组初始化失败！\n");
        return 1;
    }

    addElement(myArray, 10);
    addElement(myArray, 20);
    addElement(myArray, 30); // 触发扩容

    for (int i = 0; i < myArray->size; i++) {
        printf("Element %d: %d\n", i, myArray->data[i]);
    }

    freeDynamicArray(myArray);
    return 0;
}

typedef struct {
    int header;
    int data_length;
    char data[]; // 柔性数组成员
} Packet;

// 分配Packet结构体和数据部分的内存
Packet* createPacket(int header, int data_length) {
    Packet* packet = (Packet*)malloc(sizeof(Packet) + data_length * sizeof(char));
    if (packet == NULL) {
        return NULL;
    }
    packet->header = header;
    packet->data_length = data_length;
    return packet;
}

// 使用示例
int main() {
    int data_length = 100;
    Packet* myPacket = createPacket(0x1234, data_length);
    if (myPacket == NULL) {
        printf("内存分配失败！\n");
        return 1;
    }

    // 填充数据
    for (int i = 0; i < data_length; i++) {
        myPacket->data[i] = 'A' + i % 26;
    }

    // ... 使用数据 ...

    free(myPacket);
    return 0;
}