split_file.cpp

#include <iostream>   // Including the input/output stream library
#include <fstream>    // Including the file stream library
#include <string>     // Including the string handling library
#include <vector>     // Including the vector container

// Function to split a file into smaller chunks
void splitFile(const std::string & inputFile, const std::string & outputPrefix, int chunkSize) {
    // Open the input file in binary mode
    std::ifstream input(inputFile, std::ios::binary); // Open the input file in binary mode

    if (input.is_open()) { // Check if the input file was successfully opened
        // Get the file size
        input.seekg(0, std::ios::end); // Move the file pointer to the end of the file
        std::streampos fileSize = input.tellg(); // Get the current position of the file pointer, indicating the file size
        input.seekg(0, std::ios::beg); // Move the file pointer back to the beginning of the file

        // Calculate the number of chunks
        int numChunks = (fileSize + chunkSize - 1) / chunkSize; // Calculate the number of chunks based on file size and chunk size

        // Read and write each chunk
        for (int i = 0; i < numChunks; ++i) { // Iterate through each chunk
            // Create or overwrite the output file with an incremental suffix
            std::ofstream output(outputPrefix + std::to_string(i + 1) + ".txt", std::ios::binary); // Create or overwrite the output file

            if (output.is_open()) { // Check if the output file was successfully opened
                std::vector<char> buffer(chunkSize); // Create a buffer to hold the chunk data

                // Read a chunk of data from the input file
                input.read(buffer.data(), chunkSize); // Read chunkSize number of bytes into the buffer

                // Write the chunk to the output file
                output.write(buffer.data(), input.gcount()); // Write the read data from the buffer to the output file

                output.close(); // Close the output file
            } else {
                std::cout << "Failed to open output file: " << outputPrefix + std::to_string(i + 1) + ".txt" << std::endl; // Display an error message if output file opening failed
            }
        }

        input.close(); // Close the input file

        std::cout << "File split successfully." << std::endl; // Display a success message after splitting
    } else {
        std::cout << "Failed to open the input file." << std::endl; // Display an error message if input file opening failed
    }
}

int main() {
    std::string inputFile = "merged_test_file.txt"; // Input file
    std::string outputPrefix = "part_"; // Prefix for output files
    int chunkSize = 400; // Chunk size in bytes
    splitFile(inputFile, outputPrefix, chunkSize); // Call the function to split the file
    return 0; // Return 0 to indicate successful execution
}