Nuclei

//Program written to write 0xFF to all bytes within a given file.
#include <iostream>
#include <string>
#include <fstream>
#include <limits>

using namespace std;

string filepath;

int main()
{
    cout << "Enter the directory of the file you wish to write to:\n"; //Ask for the directory
    cin >> filepath; //Store the directory in filpath
    ofstream file; //Set file as a file
    file.open (filepath,ios::in|ios::out|ios::binary|ios::trunc); //Open filepath in binary mode, with in/out, and truncating the existing text.
    long int * memory, *p, x; //Create memorycheck, memory, and p pointers
    memory = new long int[0]; //Request 1 byte of dynamic memory
    p = memory;
    x = &p;
    for (; x > 0; ); //Write 0xFF to the address P, move on to the previous byte, and repeat until beginning of file reached.
    {
        *p = 0xFF;
        x--;
        &p = x;
    }
    file << memory[p]; //Write all the newly overwritten memory to the file.. I think.
    cout << "0 written to all bytes. Press [Enter] to exit..\n"; //Displaying the finished message.
    std::cin.ignore( std::numeric_limits<std::streamsize>::max(), '\n' ); //Thanks, Duoas. xD..

    return 0;
}