generating random numbers for 1,000,000 elements

[mqueene7]

In my code I want to be able to generate up to 1000000 numbers. Will my random number generator do this without crashing? If not, can someone assist me in what I need to do?

thank you

int main()
{ 
    int num,i,elem, percent;
    a[num];
    cout<<"Please Enter THE NUMBER OF ELEMENTS you want to sort[THEN PRESS ENTER]:"<<endl;
    cin>>num;
    cout<<"Please Enter THE PERCENTAGE you want to sort[THEN PRESS ENTER]:"<<endl;
    cin>>percent;
    for (i=1; i<=num; i++)
    {
        elem =((rand()*9)+1);
        cout<<endl<<"element "<<i<<"is "<<elem<<endl;
        a[i]= elem;
        cout<<"When i is "<<i<<" ai is "<<a[i];
    }
    merge_sort(1,num);
    cout<<endl<<"So, the sorted list (using MERGE SORT) will be : "<<endl;
    for(i=1;i<=num;i++)
    {
         cout<<a[i]<<" ";
    }
    cout<<endl<<"Time Elapsed is: "<<timeElapsed<<endl<<endl<<endl<<endl<<endl;
    system("PAUSE");
return 0;
}

[Ganon11]

As long as you don't ask for more than INT_MAX numbers, you should be fine.

[weaknessforcats]

Your array of random numbers is on the stack. You might find that you crash. If so, create your array on the heap.

[mqueene7]

Your array of random numbers is on the stack. You might find that you crash. If so, create your array on the heap.

How do i create it on the heap?

[RRick]

Since num is the number of entries, to create an int array of num entries:

int *iarray = new int[ num];
 
//  Also, what you new, you must delete
delete [] iarray;
 

Its not a good idea to multiply the random number, because the set of random numbers can cover all positive values of int. Line #11, might cause an integer overflow. Once that happens, your random number sequence might have repeat values.