Count the Number of Lines in a File in C

Introduction

This article will guide you through the process of writing a program to count the number of lines in a file using the C programming language.

In the realm of programming, counting the number of lines in a file is a common task that developers often encounter.

Also Read: Search a Character in a String Using a Pointer in C

Whether you are working on a simple text file or a complex dataset, knowing how to efficiently count the lines can be incredibly useful.

By the end, you will have a solid understanding of how to tackle this task with confidence.

The Basics of File Handling in C

Before diving into the specifics of counting lines in a file, let’s first discuss the basics of file handling in the C programming language.

Also Read: Print Contents of File in Reverse Order in C

C provides a rich set of functions and libraries that enable you to interact with files seamlessly. One of the key concepts to grasp is the concept of a file pointer.

A file pointer is a variable that keeps track of the position within a file. It allows you to perform various operations such as reading, writing, and seeking within the file.

In our case, we will be focusing on reading the contents of a file to count the lines.

Also Read: C Program To Read Two Files Simultaneously

Opening a File

The first step in counting the number of lines in a file is to open the file for reading. In C, you can use the fopen() function to achieve this.

Also Read: Armstrong Number in C Programming

Let’s take a look at the code snippet below:

#include <stdio.h>

int main() {
    FILE *file;
    char *filename = "example.txt";
    
    file = fopen(filename, "r");
    
    if (file == NULL) {
        printf("Failed to open the file.");
        return 1;
    }
    
    // Rest of the code goes here
    
    fclose(file);
    return 0;
}

In the code above, we declare a file pointer variable file and a character pointer filename that holds the name of the file we want to open.

The fopen() function takes two arguments: the filename and the mode in which we want to open the file. In this case, we use "r" to open the file in read mode.

Also Read: C Program to Find the Inverse of 2×2 Matrix

Counting the Lines

With the file successfully opened, we can now proceed to count the number of lines.

One approach to accomplish this is by reading the file character by character and checking for newline characters ('\n').

Also Read: C Program to Copy the Contents of One File into Another File

Let’s take a look at the code snippet below:

#include <stdio.h>

int main() {
    FILE *file;
    char *filename = "example.txt";
    int lineCount = 0;
    char ch;
    
    file = fopen(filename, "r");
    
    if (file == NULL) {
        printf("Failed to open the file.");
        return 1;
    }
    
    while ((ch = fgetc(file)) != EOF) {
        if (ch == '\n') {
            lineCount++;
        }
    }
    
    printf("The number of lines in the file is: %d", lineCount);
    
    fclose(file);
    return 0;
}

In the code above, we introduce an integer variable lineCount to keep track of the number of lines.

We then use a while loop to iterate through the file character by character using the fgetc() function.

Also Read: Getchar and Putchar Function in C with Example

If we encounter a newline character ('\n'), we increment the lineCount variable.

Finally, we display the result by printing the value of lineCount using the printf() function.

After that, we close the file using the fclose() function to free up system resources.

Also Read: Best 5 Programs on Fibonacci Series in C

Frequently Asked Questions

Conclusion

Counting the number of lines in a file is a fundamental task in programming, and understanding how to accomplish it efficiently is essential.

Also Read: Program To Reverse a String in C using Pointer

In this article, we explored the process of counting lines in a file using the C programming language.

We covered the basics of file handling, opening a file, and implementing a line counting algorithm.

Also Read: 25 Tricky Questions on Pointers in C: Explained and Answered

Additionally, we addressed common questions and provided insights into handling errors and working with different file types.

Armed with this knowledge, you can confidently count the number of lines in a file in C and apply this skill to various programming projects.