Passing random numbers to a function

[grigorianvlad]

Hi.I am learning C++.

I need to build code that does the following.

1) Generates 3 random numbers and passes them to next function
2) Next function uses these three different random numbers (lets say 66762734234234234, 9234234234444444444, 3545345555555) to pass them to x, y and z, which are then added. The numbers are large, so bigint is used.
3) The result is appended to text file.The file should look like this:
934855435345345435
4353453454354354555
345345435435436543534534
etc

So, the code should not prompt user for anything, just write lets say a million of added x,y and z to a text file.

The code below does what described above, except I dont know how to pass the random numbers to x, y and z. They are just printed on screen without being used by the following function. They are not connected with the addition function. Its just some snippet I found on the net.

Question.

How do I alter the code so random numbers (different for every increment and pass) are passed to the x, y and z.

Thanks.
V.

Start of code:

#include <iostream> 
#include <fstream>
#include <ctime> 
#include <cstdlib>
#include "BigIntegerLibrary.hh"

BigInteger _pow(BigInteger &base, const BigUnsigned power, BigInteger *res)
{
  *res = 1;
  for (BigUnsigned i(0); i < power; i ++)
  {
      *res *= base;
  }
  return *res;
}

using namespace std;
int main()
{
    { 
          /* Random numbers generator, not plugged in yet */
    srand((unsigned)time(0)); 
    int random_integer; 
    int lowest=1000000, highest=100000000; 
    int range=(highest-lowest)+1; 
    for(int index=0; index<20; index++){ 
        random_integer = lowest+int(range*rand()/(RAND_MAX + 1.0)); 
        cout << random_integer << endl; 
  }
  
  /* End of random numbers generator */

 std::string s;
 
 BigInteger x, y, z;
 using std::cout;
 using std::cin;
 using namespace std;
 ofstream myfile;
 
 /* Start of large number addition function, random numbers from above are 
 supposed to be passed to x, y and z instead of prompting users to enter them. 
 The random numbers should be different for each x, y and z on every line output below */
 
 cout << "Please enter x: ";
 cin >> s;
 x = stringToBigInteger(s);
 cout << "Please enter y: ";
 cin >> s;
 y = stringToBigInteger(s);
 cout << "Please enter z: ";
 cin >> s;
 z = stringToBigInteger(s);

 BigInteger res;
  std::cout << "Adding numvers: \n";
  std::cout << (x + y + z) ;
  std::cout << std::endl;
  /* End of large number addition function */
  
  /* Start of file writing function */
  myfile.open ("vdb_similar.txt", ios::app ); 
  /* Separate entries in datafiles in new lines */
  myfile << "\n";
  /* Write run length on new line */ 
  myfile << (x + y + z) ;
  myfile.close();
  std::cout << "Done writing, closed datafile\n";
  system("pause");
  return 0;
  }
}