Reading a text file

How to:

To start reading a text file in C, you primarily work with the fopen(), fgets(), and fclose() functions from the standard I/O library. Here’s a simple example that reads a file called example.txt and prints its contents to the standard output:

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

int main() {
    FILE *filePointer;
    char buffer[255]; // Buffer to store the text lines

    // Open the file in read mode
    filePointer = fopen("example.txt", "r");

    // Check if the file was opened successfully
    if (filePointer == NULL) {
        printf("Could not open file. \n");
        return 1;

    while (fgets(buffer, 255, filePointer) != NULL) {
        printf("%s", buffer);

    // Close the file to free resources
    return 0;

Assuming example.txt contains:

Hello, World!
Welcome to C programming.

The output would be:

Hello, World!
Welcome to C programming.

Deep Dive

Reading files in C has a rich history, tracing back to the early days of Unix when the simplicity and elegance of text streams were fundamental. This led to the adoption of text files for a myriad of purposes, including configuration, logging, and inter-process communication. The simplicity of the C language’s file I/O library, exemplified by functions like fopen(), fgets(), and fclose(), underlines its design philosophy of providing basic tools that programmers can use to build complex systems.

Historically, while these functions have served countless applications well, modern programming practices have highlighted some limitations, especially regarding error handling, file encoding (e.g., Unicode support), and concurrent access in multi-threaded applications. Alternative approaches in other languages, or even within C using libraries like libuv or Boost.Asio for C++, offer more robust solutions by addressing these concerns directly with more sophisticated I/O management capabilities, including asynchronous I/O operations that can greatly improve the performance of applications dealing with extensive file reading operations or I/O bound tasks.

Despite these advancements, learning to read files using the standard I/O library in C is crucial. It not only helps understand the basics of file handling, which are applicable in many programming contexts but also provides a foundation upon which one can appreciate the evolution of file I/O operations and explore more complex libraries and frameworks for file handling in modern applications.