C语言中为指针的指针动态分配内存空间的做法

#include "stdafx.h"
//输出数组测试
void PrinT(int *p,int size){
for (size_t i = 0; i < size; i++)
{
printf("%d ", p[i]);
}
printf("\n")
4000
;
}
int _tmain(int argc, _TCHAR* argv[])
{
int **p;
int GroupSize = 5;//外层size
int innerSize = 2;//内层size
//申请由外到内
p = (int**)malloc(sizeof(int*)*GroupSize);
for (size_t i = 0; i < GroupSize; i++)
{
//p[i]是一个innerSize大小的int数组的首地址
p[i] = (int*)malloc(sizeof(int)*innerSize);
for (size_t j = 0; j < innerSize; j++)
{
p[i][j] = i+j;
}
PrinT(p[i], innerSize);
}
//释放从内到外
for (size_t i = 0; i < innerSize; i++)
{
free(p[i]);
}
free(p);
return 0;
}