C++ File handling: Open and display text file contents

Last update on December 20 2024 12:22:51 (UTC/GMT +8 hours)

Write a C++ program to open an existing text file and display its contents on the console.

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 an existing file named "test.txt"
  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

    while (std::getline(inputFile, line)) {  // Loop through each line in the file
      // Display each line on the console
      std::cout << line << std::endl;  // Output the content of 'line' to the console
    }

    inputFile.close();  // Closing the file after reading
  } 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:

C++ is a high-level, general-purpose programming language created by Danish computer scientist Bjarne Stroustrup.
First released in 1985 as an extension of the C programming language, it has since expanded significantly over time.
Modern C++ currently has object-oriented, generic, and functional features, in addition to facilities for low-level memory manipulation.
It is almost always implemented in a compiled language.
Many vendors provide C++ compilers, including the Free Software Foundation, LLVM, Microsoft, Intel, Embarcadero, Oracle, and IBM.

Explanation:

In the above exercise -

• Use the std::ifstream class to open an existing file named "example.txt".
• Check if the file was successfully opened using the is_open() function.
• If the file is open, use a while loop and std::getline() to read each line from the file and store it in the line variable.
• Display each line on the console using std::cout.

After running this program, it will open the "example.txt" file (assuming it exists in the same directory as the program) and display its contents on the console.

Flowchart:

CPP Code Editor:

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