About Text and Binary files,end of file indicator

[Awareness]

I open a file in text mode(for example mode "r+"),and then I use fwrite function and write a struct into a file.Now when I look inside the file with Notepad(for example),I can't read the entries.So they are not text files ,maybe binary files?But I didn't open the file in binary mode?

My next question is,if I open a file in text mode ,if I write using fwrite and structs,try to read it's entries using fread, and if there is the number "26" inside one of the structs,then it continues reading up to 26,and without printing 26 and next numbers,it stops reading from file..

For example:

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

struct structure
{
  int num;
}structure1;

int main()
{
 FILE* fp;
 if ((fp = fopen("file1.ntt","w+")) ==0)
 {
   exit(1);
 }

 for (int i=1;i<45;i++)
 {
   structure1.num=i;
   fwrite(&structure1,sizeof(struct structure),1,fp);
  }

   rewind(fp);

 while(feof(fp)==0)
 {
  fread(&structure1,sizeof(struct structure),1,fp);
  printf("%d",structure1.num);
 }

}

This program reads until num value becomes 26,then it stops reading.
I have read that character "z" (and it's ascii code "26") is used as end of file indicator.So this looks like the reason of the problem,but I haven't been able to find a solution other than simply opening the file in binary format(for example w+b) or using functions other than fwrite.