CBSE Class 12 Computer Science: Chapter 6 Data File Handling NCERT Solutions

To count the words in a text file, we can read the file word by word and increment a counter for each word read. The stream extraction operator `>>` is suitable for this as it reads until whitespace.

Here is the C++ function:

#include <iostream>

#include <fstream>

#include <string>

void word_count() {

std::ifstream inputFile("opinion.txt");

std::string word;

int count = 0;

if (inputFile.is_open()) {

// Read words until the end of the file is reached

while (inputFile >> word) {

count++; // Increment count for each word read } inputFile.close();

std::cout << "Total number of words present in the text file are: " << count << std::endl;

} else {

std::cout << "Error opening file." << std::endl; } }

Explanation:

• The function `word_count` uses an `ifstream` object to open `"opinion.txt"`.
• A `std::string word` is used to store each word read from the file.
• The `while (inputFile >> word)` loop continues as long as words can be successfully extracted from the file.
• Inside the loop, `count` is incremented for every word read.
• Finally, the total count is displayed. Error handling for file opening is included.

This function will read the file word by word and check the length of each word. If a word has exactly three letters, a counter is incremented. The final count is then displayed.

Here is the C++ function:

#include <iostream>

#include <fstream>

#include <string>

#include <cstring> // For strlen

void countThreeLetterWords() {

std::ifstream inputFile("VOWEL.TXT");

char word[80];

int count = 0;

if (inputFile.is_open()) {

// Read words from the file

while (inputFile >> word) {

// Check if the length of the word is exactly 3

if (strlen(word) == 3) {

count++; } }

inputFile.close();

std::cout << "Number of three letter words = " << count << std::endl;

} else {

std::cout << "Error opening file." << std::endl; } }

Explanation:

• The function `countThreeLetterWords` opens `"VOWEL.TXT"` using `ifstream`.
• It reads words into a character array `word`.
• `strlen(word)` calculates the length of the current word.
• If the length is exactly 3, the `count` is incremented.
• After reading the entire file, the total `count` is printed.

This function reads the file character by character and checks if each character is 'A', 'a', 'E', or 'e'. Counters are maintained for 'A'/'a' and 'E'/'e' occurrences, and the final counts are displayed.

Here is the C++ function:

#include <iostream>

#include <fstream>

void AECount() {

std::fstream file("NOTES.TXT", std::ios::in);

char ch;

int countA = 0;

int countE = 0;

if (file.is_open()) {

// Read characters until the end of the file

while (file.get(ch)) {

// Check if the character is 'A' or 'a'

if (ch == 'A' || ch == 'a') {

countA++; } // Check if the character is 'E' or 'e'

else if (ch == 'E' || ch == 'e') {

countE++; } }

file.close();

std::cout << "A: " << countA << " E: " << countE << std::endl;

} else {

std::cout << "Error opening file." << std::endl; } }

Explanation:

• The function `AECount` uses an `fstream` object to open `"NOTES.TXT"` in input mode (`std::ios::in`).
• The `while (file.get(ch))` loop reads the file one character at a time.
• Inside the loop, `if` and `else if` statements check if the character `ch` matches 'A'/'a' or 'E'/'e'.
• Corresponding counters (`countA`, `countE`) are incremented.
• After processing all characters, the counts are displayed.