Simple Encryption not working - c++

Question

I'm using a simple encryption that I found online. Basically, I'm streaming in a file, checking to see if that file is open (if not, display an error message) and putting each line in each element of the array while encrypting the information. Afterwards I stream that encrypted information onto an output file.
However, I'm getting nothing in my output.txt file. The encryption works fine if you test it by itself.
Here is my code:
#include <string>
#include <fstream>
#include <sstream> // for ostringstream
#include <iostream>
#include <stdio.h>
#include <algorithm>
/* Credits to kylewbanks.com */
string encrypt (string content) {
char key[3] = {'K'}; //Any chars will work
string output = content;
for (int i = 0; i < content.size(); i++)
output[i] = content[i] ^ key[i % (sizeof(key) / sizeof(char))];
return output;
}
int main() {
string input, line;
string content[10000];
string encryptedContent[10000];
int counter = 0, innerChoice = 0, i, finalCounter;
cout << "\tPlease enter the file name to encrypt!\n";
cout << "\tType '0' to get back to the menu!\n";
cout << "Input >> ";
cin >> input;
/* Reads in the inputted file */
ifstream file(input.c_str());
//fopen, fscanf
if(file.is_open()) {
/* Counts number of lines in file */
while (getline(file, line)) {
counter++;
}
cout << counter;
finalCounter = counter;
for (i = 0; i < finalCounter; i++) {
file >> content[i];
encryptedContent[i] = encrypt(content[i]);
cout << encryptedContent[i];
}
} else {
cout << "\tUnable to open the file: " << input << "!\n";
}
/* Write encryption to file */
ofstream outputFile("output.txt");
for (i = 0; i < finalCounter ; i++) {
outputFile << encryptedContent;
}
outputFile.close();
}
Any clue what is wrong?

Answer 1

string content[10000];
string encryptedContent[10000];
This is wrong because it is creating 20000 strings (you probably think it is creating a large enough character array to read the data).
string content; is enough. It can be resized to handle any length of strings.
You just need to read/write the file in binary:
int main()
{
string input = "input.txt";
ifstream file(input, ios::binary);
if (!file.is_open())
{
cout << "\tUnable to open the file: " << input << "!\n";
return 0;
}
string plaintext;
//read the file
file.seekg(0, std::ios::end);
size_t size = (size_t)file.tellg();
file.seekg(0);
plaintext.resize(size, 0);
file.read(&plaintext[0], size);
cout << "reading:\n" << plaintext << "\n";
//encrypt the content
string encrypted = encrypt(plaintext);
//encrypt again so it goes back to original (for testing)
string decrypted = encrypt(encrypted);
cout << "testing:\n" << decrypted << "\n";
/* Write encryption to file */
ofstream outputFile("output.txt", ios::binary);
outputFile.write(encrypted.data(), encrypted.size());
return 0;
}