C program to count characters, lines and number of words in a file

In C programming, counting characters, words, and lines in a file is a common file processing task. This operation reads through a file character by character and keeps track of different elements based on specific delimiters.

Syntax

FILE *fopen(const char *filename, const char *mode);
int fgetc(FILE *stream);
int fclose(FILE *stream);

File Operations Overview

The three basic operations that we can perform on files are −

• Open a file − Using fopen() function
• Process file − Read, write, or modify file contents
• Save and close file − Using fclose() function

Example: Counting File Content

The following program demonstrates how to count characters, words, and lines in a text file −

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

int main() {
    FILE *file;
    char filename[100];
    char ch;
    int characters = 0, words = 0, lines = 0;
    int inWord = 0;
    
    printf("Enter filename: ");
    scanf("%s", filename);
    
    file = fopen(filename, "r");
    if (file == NULL) {
        printf("Error: Unable to open file '%s'<br>", filename);
        return 1;
    }
    
    while ((ch = fgetc(file)) != EOF) {
        characters++;
        
        if (ch == '<br>') {
            lines++;
            if (inWord) {
                words++;
                inWord = 0;
            }
        }
        else if (ch == ' ' || ch == '\t') {
            if (inWord) {
                words++;
                inWord = 0;
            }
        }
        else {
            inWord = 1;
        }
    }
    
    /* Count the last word if file doesn't end with newline */
    if (inWord) {
        words++;
    }
    
    /* Count the last line if file doesn't end with newline */
    if (characters > 0) {
        lines++;
    }
    
    printf("\nFile Statistics:<br>");
    printf("Total characters = %d<br>", characters);
    printf("Total words = %d<br>", words);
    printf("Total lines = %d<br>", lines);
    
    fclose(file);
    return 0;
}

How It Works

The program uses the following logic −

• Character counting − Increments counter for each character read
• Word counting − Uses a flag to track when inside a word, counts transitions from word to non-word
• Line counting − Increments counter at each newline character

Sample Input File

Create a text file named sample.txt with the following content −

Hello World
This is C programming
Tutorial from TutorialsPoint

Output

When you run the program with the above input file, it produces −

Enter filename: sample.txt

File Statistics:
Total characters = 58
Total words = 8
Total lines = 3

Key Points

• Always check if file opens successfully before processing
• Use fgetc() to read one character at a time
• Handle edge cases like files not ending with newline
• Close the file with fclose() to free resources

Conclusion

File content analysis in C involves reading character by character and tracking delimiters. This approach provides accurate counting of characters, words, and lines in any text file using standard C library functions.