C++ File handling: Count number of lines in a text file

Last update on December 20 2024 12:29:14 (UTC/GMT +8 hours)

Write a C++ program to count the number of lines in a text file.

Sample Solution:

C Code:

#include <iostream>   // Including the input/output stream library

#include <fstream>    // Including the file stream library

#include <string>     // Including the string handling library

int main() {
  // Open the text file
  std::ifstream inputFile("test.txt");  // Opening the file named "test.txt" for reading

  if (inputFile.is_open()) {  // Checking if the file was successfully opened
    std::string line;  // Declaring a string variable to store each line of text
    int lineCount = 0;  // Initializing a variable to count lines

    while (std::getline(inputFile, line)) {  // Loop through each line in the file
      lineCount++;  // Incrementing line count for each line read
    }

    inputFile.close();  // Closing the file after counting lines

    std::cout << "Number of lines in the file: " << lineCount << std::endl;  // Outputting the total line count
  } else {
    std::cout << "Failed to open the file." << std::endl;  // Display an error message if file opening failed
  }

  return 0;  // Return 0 to indicate successful execution
}

Sample Output:

Number of lines in the file: 5

Explanation:

In the above exercise -

• Use the std::ifstream class to open the text file.
• Check if the file was successfully opened using the is_open() function.
• If the file is open, declare an int variable lineCount to keep track of the number of lines.
• Use a while loop and std::getline() to read each line from the file and increment the lineCount for each line read.
• After the loop ends, close the file using inputFile.close() and display the total number of lines on the console.

Flowchart:

CPP Code Editor:

Contribute your code and comments through Disqus.

Previous C++ Exercise: Open and display text file contents.
Next C++ Exercise: Count number of words in a text file.