What is value of EOF and '\ 0 ' in C

In C, EOF and '\0' are two distinct concepts, as detailed below:

1. EOF：EOF is a macro defined in stdio.h, representing "End of File" (EOF), used to indicate that no more data can be read from the file stream. In most systems, EOF is defined as -1. It is commonly used in file reading functions such as fgetc and fscanf, which return EOF when reaching the end of the file or encountering an error.

   Example:

   c
   FILE *fp = fopen("example.txt", "r");
   if (fp == NULL) {
       perror("file open failed");
       return -1;
   }
   int ch;
   while ((ch = fgetc(fp)) != EOF) {
       putchar(ch);
   }
   fclose(fp);

2. \0：\0 is a null character, used in C to mark the end of a string. Its ASCII value is 0. Strings in C are typically stored as character arrays, with the end marked by \0, so the program knows when to stop processing the string.

   Example:

   c
   char str[] = "Hello, World!";
   printf("%s\n", str);  // normally prints the string
   
   // modify the character in the string to `\0`
   str[5] = `\0`;
   printf("%s\n", str);  // only prints "Hello"

Both concepts are essential in C programming, serving different purposes in file operations and string handling.