采用malloc分别分配2KB个人空间，然后，realloc调整到6KB、1MB、3MB、10MB场地，分别这五内存“A”、“B”、“C”、“D”、“E”灌装

#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<malloc.h>
int main(void)
{
   char *str1 = NULL;
   char *str2 = NULL;
   char *str3 = NULL;
   char *str4 = NULL;
   char *str5 = NULL;
   str1 = (char*)malloc(2*1024*sizeof(char));
   if(str1==NULL)
   {
       printf("malloc error! ");
       return -1;
   }
   printf("malloc 2KB: %p ",str1);
   memset(str1,'A',2*1024*sizeof(char));
   printf("mem content:%s ",str1);
   str2 = (char*)realloc(str1,6*1024*sizeof(char));
   if(str2==NULL)
   {
       printf("realloc error! ");
       return -1;
   }
   printf("realloc 6KB: %p ",str2);
   memset(str2,'B',6*1024*sizeof(char));
   printf("mem content:%s ",str2);
   str3 = (char*)realloc(str2,1024*1024*sizeof(char));
   if(str3==NULL)
   {
       printf("realloc error! ");
       return -1;
   }
   printf("realloc 1MB: %p ",str3);
   memset(str3,'C',1024*1024*sizeof(char));
   printf("mem content:%s ",str3);
   str4 = (char*)realloc(str3,3*1024*1024*sizeof(char));
   if(str4==NULL)
   {
       printf("realloc error! ");
       return -1;
   }
   printf("realloc 3MB: %p ",str4);
   memset(str4,'D',3*1024*1024*sizeof(char));
   printf("mem content:%s ",str4);
   str5 = (char*)realloc(str4,10*1024*1024*sizeof(char));
   if(str5==NULL)
   {
       printf("realloc error! ");
       return -1;
   }
   printf("realloc 10MB: %p ",str5);
   memset(str5,'E',10*1024*1024*sizeof(char));
   printf("mem content:%s ",str5);
   free(str5);
   return 0;
}