how to open file without override c++

#include <iostream>
#include <fstream>

int main() {
    // Step 1: Declare variables
    std::ifstream inputFile;
    std::ofstream outputFile;

    // Step 2: Open input file in binary mode
    inputFile.open("input.txt", std::ios::binary);

    // Step 3: Check if the input file is successfully opened
    if (!inputFile.is_open()) {
        std::cerr << "Error opening input file." << std::endl;
        return 1; // Exit with an error code
    }

    // Step 4: Open output file in binary mode with std::ios::app flag
    outputFile.open("output.txt", std::ios::binary | std::ios::app);

    // Step 5: Check if the output file is successfully opened
    if (!outputFile.is_open()) {
        std::cerr << "Error opening output file." << std::endl;
        return 1; // Exit with an error code
    }

    // Step 6: Read data from the input file and write to the output file
    char buffer[1024];
    while (inputFile.read(buffer, sizeof(buffer))) {
        outputFile.write(buffer, inputFile.gcount());
    }

    // Step 7: Close the file streams
    inputFile.close();
    outputFile.close();

    return 0; // Exit successfully
}