C Program to count the Number of Characters in a File

Last Updated : 29 May, 2019

Counting the number of characters is important because almost all the text boxes that rely on user input have certain limitations on the number of characters that can be inserted. For example, the character limit on a Facebook post is 63,206 characters. Whereas, for a tweet on Twitter the character limit is 140 characters and the character limit is 80 per post for Snapchat.

Determining character limits become crucial when the tweet and Facebook post updates are being done through API’s.

Note: This program would not run on online compilers. Please make a text (.txt) file on your system and give its path to run this program on your system.

Approach: The characters can be counted easily by reading the characters in the file using getc() method. For each character read from the file, increment the counter by one.

Below is the implementation of the above approach:

Program:

// C Program to count 
// the Number of Characters in a Text File 
  
#include <stdio.h> 
#define MAX_FILE_NAME 100 
  
int main() 
{ 
    FILE* fp; 
  
    // Character counter (result) 
    int count = 0; 
  
    char filename[MAX_FILE_NAME]; 
  
    // To store a character read from file 
    char c; 
  
    // Get file name from user. 
    // The file should be either in current folder 
    // or complete path should be provided 
    printf("Enter file name: "); 
    scanf("%s", filename); 
  
    // Open the file 
    fp = fopen(filename, "r"); 
  
    // Check if file exists 
    if (fp == NULL) { 
        printf("Could not open file %s", 
               filename); 
        return 0; 
    } 
  
    // Extract characters from file 
    // and store in character c 
    for (c = getc(fp); c != EOF; c = getc(fp)) 
  
        // Increment count for this character 
        count = count + 1; 
  
    // Close the file 
    fclose(fp); 
  
    // Print the count of characters 
    printf("The file %s has %d characters\n ", 
           filename, count); 
  
    return 0; 
} 