分别在堆上和栈上分配空间

#define _CRT_SECURE_NO_WARNINGS
#include<stdio.h>
#include<string.h>
#include<stdlib.h>
void printArray(int **arr,int len)
{
    for (int i = 0; i < len; ++i)
    {
        printf("%d ",*arr[i]);
    }
}
void test01()
{
    //堆上分配指针数组
    int **pArray = malloc(sizeof(int *)* 6);
    //栈上分配数据空间
    int a1 = 100;
    int a2 = 200;
    int a3 = 300;
    int a4 = 400;
    int a5 = 500;
    int a6 = 600;
#if 0
    pArray[0] = &a1;
    pArray[1] = &a2;
    pArray[2] = &a3;
    pArray[3] = &a4;
    pArray[4] = &a5;
    pArray[5] = &a6;
#endif
    *(pArray + 0) = &a1;
    *(pArray + 1) = &a2;
    *(pArray + 2) = &a3;
    *(pArray + 3) = &a4;
    *(pArray + 4) = &a5;
    *(pArray + 5) = &a6;
    printArray(pArray, 6);
    //释放数组内存
    if (pArray != NULL)
    {
        free(pArray);
        pArray = NULL;
    }
}
void test02()
{
    int* pArray[5];
    for (int i = 0; i < 5; ++i)
    {
                //一个个申请
        pArray[i] = malloc(4);
        *(pArray[i]) = 100 + i;
    }
    printArray(pArray, 5);
    //释放堆内存
    for (int i = 0; i < 5; ++i)
    {
        if (pArray[i] != NULL)
        {
                        //要一个个释放
            free(pArray[i]);
            pArray[i] = NULL;
        }
    }
}
int main(){
    //test01();
    test02();
    system("pause");
    return EXIT_SUCCESS;
}

二级指针做函数参考

#include <iostream>
#include <stddef.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
void allocateSpace(int **temp) {
    int *arr = (int *)malloc(sizeof(int) * 10);
    for (int i = 0; i < 10; ++i) {
        arr[i] = i + 1;
    }
    //指针间接赋值
    *temp = arr;
}
void printArray(int *arr, int len) {
    for (int i = 0; i < len; ++i) {
        printf("%d ", arr[i]);
    }
}
void freeSpace(int **arr) {
    if (arr == NULL) {
        return ;
    }
    if (*arr != NULL) {
        free(*arr);
        *arr = NULL;
        arr = NULL;
    }
}
void test01() {
    int *pArray = NULL;
    allocateSpace(&pArray);
    printArray(pArray, 10);
    freeSpace(&pArray);
    if (pArray == NULL) {
        printf("\npArray被置空");
    }
}
int main() {
    test01();
    getchar();
    return 0;
}