Copy File

Copying a File in C++

IntermediateTopic: File Handling Programs
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C++ Copy File Program

This program helps you to learn the fundamental structure and syntax of C++ programming.

Try This Code
#include <iostream>
#include <fstream>
#include <filesystem>
using namespace std;
using namespace filesystem;

int main() {
    string sourceFile = "data.txt";
    string destFile = "data_copy.txt";
    
    // Method 1: Using filesystem (C++17) - Simple
    try {
        copy_file(sourceFile, destFile);
        cout << "File copied successfully using filesystem!" << endl;
    } catch (const filesystem_error& e) {
        cout << "Error: " << e.what() << endl;
    }
    
    // Method 2: Manual copy - Read and write
    ifstream source(sourceFile, ios::binary);
    ofstream dest(destFile + "_manual", ios::binary);
    
    if (source.is_open() && dest.is_open()) {
        dest << source.rdbuf();  // Copy entire file buffer
        
        source.close();
        dest.close();
        
        cout << "File copied manually!" << endl;
    } else {
        cout << "Error opening files for manual copy." << endl;
    }
    
    // Verify copy
    if (exists(destFile)) {
        cout << "\nVerification:" << endl;
        cout << "Source size: " << file_size(sourceFile) << " bytes" << endl;
        cout << "Copy size: " << file_size(destFile) << " bytes" << endl;
        
        if (file_size(sourceFile) == file_size(destFile)) {
            cout << "File sizes match - Copy verified!" << endl;
        }
    }
    
    return 0;
}
Output
File copied successfully using filesystem!
File copied manually!

Verification:
Source size: 156 bytes
Copy size: 156 bytes
File sizes match - Copy verified!

Understanding Copy File

File copying can be done: 1) Using filesystem::copy_file() (C++17) - simplest, 2) Manual method - read from source, write to destination. Use rdbuf() to copy entire file buffer efficiently. For binary files, use ios::binary mode. Always verify the copy by comparing file sizes or contents.

Note: To write and run C++ programs, you need to set up the local environment on your computer. Refer to the complete article Setting up C++ Development Environment. If you do not want to set up the local environment on your computer, you can also use online IDE to write and run your C++ programs.

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