How do you initialize a dynamic array in C language?

In C language, dynamic arrays are initialized by allocating memory using the malloc function, and assigning the first address of the array to a pointer variable. An example code is shown below:

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

int main() {
    int size;
    printf("请输入动态数组的大小：");
    scanf("%d", &size);

    int *arr = (int*)malloc(size * sizeof(int));
    if (arr == NULL) {
        printf("内存分配失败\n");
        return 1;
    }

    // 初始化数组
    for (int i = 0; i < size; i++) {
        arr[i] = i + 1;
    }

    // 输出数组元素
    for (int i = 0; i < size; i++) {
        printf("%d ", arr[i]);
    }
    printf("\n");

    // 释放动态数组内存
    free(arr);

    return 0;
}

In the above code, first the size of the dynamic array is obtained from user input using the scanf function. Next, memory space of size * sizeof(int) is allocated using the malloc function, and its starting address is assigned to a pointer variable of type int, arr. Then, the array is initialized using a for loop, setting the values of array elements to the index value plus 1. Finally, the memory space of the dynamic array is released using the free function.