Is File a Built-in Data Type in C?


Scott Campbell

Is File a Built-in Data Type in C?

In the C programming language, there are several built-in data types such as int, float, char, etc. These data types help programmers define variables and perform various operations on them. However, the file data type is not one of the built-in data types in C.

The Need for Files in C Programs

C programs often need to read from or write to external files for various purposes, such as storing or retrieving data, logging information, handling configuration files, etc. To accomplish this, the C programming language provides a set of functions and structures that allow programmers to work with files.

The Standard Library for File Operations: stdio.h

To work with files in C, you need to include the standard library header file called <stdio.h>. This header file provides functions and structures like fopen(), fread(), fwrite(), etc., which are used to open, read from, and write to files.

The FILE Structure

Although file is not a built-in data type in C, the standard library provides a structure called FILE. This structure represents a file stream and contains information about an open file including its name, position indicator (current read/write position), error status flags, etc.

Working with Files in C

To work with files in C programs:

  • Create a FILE pointer: Declare a pointer of type FILE* to hold the reference to the file stream.
  • Open the file: Use the fopen() function to open the file in the desired mode (e.g., read, write, append).
  • Perform operations: Use functions like fread(), fwrite(), etc., to read from or write to the file.
  • Close the file: Use the fclose() function to close the file once you’re done with it.

An Example: Reading from a File

Here’s an example that demonstrates reading from a file using C:

#include <stdio.h>

int main() {
   FILE *fp;
   char c;

   fp = fopen("file.txt", "r");

   if (fp == NULL) {
      printf("Error opening file!");
      return 1;

   while ((c = fgetc(fp)) != EOF) {
      printf("%c", c);


   return 0;

In this example, we declare a FILE pointer (fp) and use the fopen() function to open a file called “file.txt” in read mode. We then use a while loop along with the fgetc() function to read each character of the file until we reach the end (EOF). Finally, we close the file using fclose().


While the file is not a built-in data type in C, the language provides the necessary tools and functions to work with files. By using the <stdio.h> header file and the FILE structure, programmers can perform various file operations like reading from or writing to files.

Remember to include <stdio.h> and follow proper error handling techniques when working with files in C. With practice and understanding, you can efficiently incorporate file operations into your C programs.

Discord Server - Web Server - Private Server - DNS Server - Object-Oriented Programming - Scripting - Data Types - Data Structures

Privacy Policy