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

typedef struct
{
 int numb;
 char name[20];
}tom;

main()
{
 tom *temp;
 int i;
 temp=NULL;
 temp=realloc(temp,sizeof(tom)*4);

 if(temp==NULL)/*check*/
  {printf("temp==NULL\n");exit(0);}

 for(i=0;i<4;i++)/*enter number and names*/
  {
   printf("numb&name> ");
   scanf("%d %s",&temp[i].numb,&temp[i].name);
  }

  for(i=0;i<4;i++)
   printf("%s %d\n",temp[i].name,temp[i].numb);
 /* temp=realloc(temp,sizeof(tom)*3); 
 printf("free the last one\n"); */
 temp=realloc(temp,0);
 printf("free the block\n");
 for(i=0;i<4;i++)
 {
 if((temp[i].numb!=NULL)&&(temp[i].name!=NULL))
  printf("%d %s\n",temp[i].numb,temp[i].name);
 else printf("NULL\n");
 }
 printf("Now, realloc...\n");
 temp=realloc(temp,sizeof(tom)*4);
 for(i=0;i<4;i++)
 {
 if((temp[i].numb!=NULL)&&(temp[i].name!=NULL))
  printf("%d %s\n",temp[i].numb,temp[i].name);
 else printf("NULL\n");
 }
}