c语言中多维（层）结构指针的申请与释放

#include
#include
#include

typedef struct _M {
int plen;
char *p;
char pp[20];
} MM;

main()
{
MM **ss;
int i;
char str[20];

strcpy(str,"sasfdfs");  ss=(MM **)malloc(sizeof(MM *)*1000);  for(i=0;i<1000;i  ){  ss[i]=malloc(sizeof(MM));  ss[i]->p=(char *)malloc(sizeof(char *)*100); }    for(i=0;i<1000;i  ){  memcpy(ss[i]->p,str,7); }    for(i=0;i<1000;i  ){  if(ss[i]->p)free(ss[i]->p);  if (ss[i])free(ss[i]); } if(ss)free(ss); 

}