C Program to Write a Sentence to a File

#include <stdio.h>
#include <stdlib.h>
#include<conio.h>
void main(){
   char *s;
   FILE *fw;
   clrscr();
   fw = fopen("xyz.txt","w"); 
   if( fw == NULL )
   {
      printf("Error while opening the file.
");
      getch();
      exit(0);
   }
   printf("Enter a sentence:
");
   gets(s);
   fprintf(fw,"%s", s);
   fclose(fw);
   getch();
}