Sortare prin interclasare

#include <iostream>
#include <ctime>
#include <cstdlib>

using namespace std;

int a[10], n = 10;

void Generare()
{
    srand(time(0));
    for(int i = 1; i <= n; i++)
        a[i] = rand() % 10;
}

inline void Sch(int &x, int &y)
{
    int aux;
    if(x > y)
    {
        aux = x;
        x = y;
        y = aux;
    }
}

void Afisare()
{
    for(int i = 1; i <= n; i++)
        cout << a[i] << " ";
}

//Interclaseaza secv. a[st...m] si a[m+1...dr]
void Interclasare(int st, int dr, int m)
{
    int i, j, k;
    int b[1000];
    i = st;
    j = m+1;
    k = 0;
    while(i <= m && j <= dr)
        if(a[i] <= a[j]) b[++k] = a[i++];
        else b[++k] = a[j++];
    while(i <= m)
        b[++k] = a[i++];
    while(j <= dr)
        b[++k] = a[j++];
    //Transfer din b[1...k] in a[st...dr]
    j = st;
    for(i = 1; i <= k; i++)
        a[j++] = b[i];
}

void MergeSort(int st, int dr)
{
    int m;
    if(dr-st <= 1) //Intervalul [st..dr] are lungimea egala cu 1 sau 2
        Sch(a[st], a[dr]);
    else
    {
        m = (st+dr) / 2;
        MergeSort(st, m);
        MergeSort(m+1, dr);
        Interclasare(st, dr, m);
    }
}

int main()
{
    Generare();
    Afisare();
    cout << "\n";

    MergeSort(1, n);
    Afisare();
    cout << "\n";
    return 0;
}