[C] Using string point to write into file

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

#define OUT "./a.txt"
int main()
{
   FILE *fpw;
   char *p="HELLO";

   fpw=fopen(OUT, "w");
      if(fpw == NULL) return 1;

   fputs(p,fpw);
   fclose(fpw);
}


cat a.txt
HELLO