Đọc ghi file trong C

#include <stdio.h>
#include <conio.h>
main()
{
 FILE *f;
 char s[50];
 // Tao file moi
 f = fopen("abc.txt","w");
 fprintf(f,"Tao file ne.");
 fclose(f);
 // Doc file
 f = fopen("abc.txt","r");
 fgets(s,50,f);
 printf("%s",s);
 fclose(f);
 // Ghi tiep vao 1 file
 f = fopen("abc.txt","a");
 fprintf(f,"Bo sung ne.");
 fclose(f);
 getch();
}