Result: runtime error (SIGSEGV)

[abdalimran]

I've written the following code to count average. In my PC program works fine. But when I submit it into OJ, it shows Result: runtime error (SIGSEGV)

What does it mean by Result: runtime error (SIGSEGV)?
What is the problem in my code?

#include <iostream>

using namespace std;

int main()
{
    int t,n;
    int num[n];

    cin>>t;

    while(t--)
    {
        double sum=0;

        cin>>n;

        for(int i=0; i<n; i++)
        {
            cin>>num[i];
            sum+=num[i];
        }

        cout.precision(2);
        cout <<fixed<<sum/n<<endl;
    }


    return 0;
}

[Peter87]

ProgGeek wrote:

What does it mean by Result: runtime error (SIGSEGV)?

It's a segmentation fault. It happens when your program tries to access memory in ways that are not allowed.
http://en.wikipedia.org/wiki/Segmentation_fault

ProgGeek wrote:

What is the problem in my code?

You are using an uninitialized variable to set the length of the array.

[abdalimran]

Thanks a lot Peter87 (5640). :D