Getting runtime error. why does this happen?

[RAKHI2014]

include

define max 1000000007

define size 50

using namespace std;
int main()
{
int x,y[size],a[size],n;
int t;
cin>>t;
for(int i=1;i<=t;i++)
{
int k=0;
cin>>a[i];
for(x=1;x<=a[i];x++)
{
y[x]=(a[i]/x);
k=(k+(y[x]*x));
}
cout<<(k%max);
}
return 0;
}

[leppyr64]

Which problem are you trying to solve? Please use code tags when posting code.