text: #include <stdio.h>
  #include <stdlib.h>
  #include <string.h>
  int main(void)
  {
     char *p1="abcdefg";
     char *p2=(char *)malloc(10*sizeof(char));
     char *p3=memcpy(p2,p1,10);
     printf("*p3=%s,*p2=%s",p3,p2);
     free(p2);
     return 0;
  }
  