//* Reading and writing data in binary mode - copy file exmaple *
#include <iostream>
#include <fstream>
#include <string>
using namespace std;

int main() {
    // can be used both with char[] and string, it does not matter
    string inName;
    string outName;
    // prompting user for filenames
    cout << "Read text from: ";
    getline(cin,inName);
    cout << "Write text to: ";
    getline(cin,outName);

    ifstream inFile;
    ofstream outFile;

    inFile.open(inName, ios::in|ios::binary);
    if (!inFile.is_open()) {
        cout << "ERROR: Cannot open " << inName << " file for reading." << endl;
        return(1);
    }
    
    
    outFile.open(outName, ios::out|ios::binary);
    if (!outFile.is_open()) {
        cout << "ERROR: Cannot open " << inName << " file for writing." << endl;
        inFile.close();
        return(1);
    }

    // reading-writing loop
    for (;;) {
        char buffer[256];      // this is the largest chunk of data we can read at a time

        // read UP TO 256 bytes, the actual number of bytes read is returned
        inFile.read(buffer, sizeof(buffer));
        unsigned long bytes_read = inFile.gcount();
        // you must not assume that always requested number of bytes is read 
        // because of last reminder of bytes at the end of the file

        // DO NOT use inFile.readsome(,) instead the code used above
        // - unlike the textbook says IT IS NOT equivalent to the two liens above

        if (bytes_read==0) break;
        // cout << " " << bytes_read;

        outFile.write(buffer, bytes_read);
        if (outFile.fail()) {
            outFile.clear();
            cerr << "ERROR: writing to file failed!" << endl;
            break;
        }
    }
    inFile.clear();
    inFile.close();
    outFile.close();

    return(0);
}