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

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 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

Quote:

Originally Posted by weaknessforcats

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:

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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.

generating random numbers for 1,000,000 elements

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re: generating random numbers for 1,000,000 elements

re: generating random numbers for 1,000,000 elements

re: generating random numbers for 1,000,000 elements

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