C Exercises: Count the number of words and characters in a file

Last update on December 20 2024 13:04:01 (UTC/GMT +8 hours)

Write a program in C to count the number of words and characters in a file.

To count the number of words and characters in a file using C, open the file for reading, then iterate through its contents character by character. Use a counter to keep track of characters and another to count words, incrementing the word counter each time you encounter a space or newline that follows a non-space character. Finally, output the counts of words and characters.

Pseudocode Plan

File Opening:

Open the file in read mode.
Check if the file is successfully opened.

Initialization:

Initialize counters for words and characters.
A flag to track if the last character read was a whitespace.

File Reading Loop:

Read characters from the file one by one.
Print each character.
Increment character counter if the character is not EOF.
Check for word boundaries:

Increment the word counter if the current character is not a whitespace and the last character was a whitespace.

Update the last character read flag.

Final Output:

Print the total count of words and characters.

Close File:

Close the file.

Sample Solution:

C Code:

#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
int main() 
{ 
    FILE *fptr; 
    char ch; 
    int words = 0, characters = 0;
    int inWord = 0;  // Flag to check if inside a word
    char fname[20];

    printf("\n\nCount the number of words and characters in a file:\n");
    printf("---------------------------------------------------------\n"); 
    printf("Input the filename to be opened: ");
    scanf("%s", fname);    

    fptr = fopen(fname, "r"); 
    if(fptr == NULL) 
    { 
        printf("File does not exist or cannot be opened.\n"); 
        return 1;
    } 

    printf("The content of the file %s are:\n", fname); 
    while ((ch = fgetc(fptr)) != EOF) 
    { 
        putchar(ch); 
        characters++; 

        if (isspace(ch)) 
        { 
            inWord = 0; 
        } 
        else if (!inWord) 
        { 
            inWord = 1;
            words++; 
        } 
    }
    fclose(fptr); 

    printf("\nThe number of words in the file %s are: %d\n", fname, words); 
    printf("The number of characters in the file %s are: %d\n", fname, characters); 

    return 0;
}

Output:

Count the number of words and characters in a file:
---------------------------------------------------------
Input the filename to be opened: test1.txt
The content of the file test1.txt are:
test line 1
test line 2
test  line 3
test   line 4
The number of words in the file test1.txt are: 12
The number of characters in the file test1.txt are: 50

Explanation:

isspace(ch): This function checks if the character is a whitespace (space, newline, tab, etc.).
inWord flag: Keeps track of whether we are inside a word or not.
Word count: Incremented only when a non-whitespace character is found after a whitespace sequence.
Character count: Incremented for every character read from the file.

Flowchart:

C Programming Code Editor:

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