Wykonywanie algorytmu na dwa rdzenie

#include <iostream>
#include <stdlib.h>
#include <time.h>
#define N 100000
using namespace std;
int Rand( int mx, int mn ) {
    return rand() %( mx - mn + 1 ) + mn;
}
double obliczSekundy( clock_t czas )
{
    return static_cast < double >( czas ); // CLOCKS_PER_SEC;
}
void czekaj( int iMilisekundy )
{
    clock_t koniec = clock() + iMilisekundy * CLOCKS_PER_SEC / 1000.0;
    while( clock() < koniec ) continue;
   
}
int main() {
    double difference;
    std::cout.setf( ios::fixed );
    std::cout.precision( 128 );
    clock_t start, end;
    int tab[ N ];
    start = clock();
    for( int i = 0; i < N / 2; ++i ) { // TO LICZY 1 Rdzeń
        tab[ i ] = Rand( 10, - 10 );
        cout << " " << i;
    } cout << "\nBUMMMM!!\n"; czekaj( 5000 );
    for( int i = N / 2; i < N; ++i ) { // To liczy 2 rdzeń
        tab[ i ] = Rand( 10, - 10 );
        cout << " " << i;
    } cout << "\n";
    end = clock(); //czas końca
    difference =( end - start ) /( double ) CLOCKS_PER_SEC;
    std::cout << "time: " << difference << "\n";
}