WHY AM I GETTING RUN ERROR?

#1

I would like to know when do i get a run error while submitting the code.
I submit the following code for maximum subarray sum and the code was compiled successfully:

#include
using namespace std;

int main() {
int t,a[10000];
long int n;
cin>>t;
a[-1]=0;
while(t>0)
{
cin>>n;
for(int i=0 ; i<n ; i++)
{
cin>>a[i];
a[i]+=a[i-1];

	}
//sub array

int csum=0,msum=0;
for(int i=0 ; i<n-1 ; i++)
{
if(msum<a[i])
msum=a[i];

	for(int j=i+1 ; j<n ; j++)
	{
      csum=a[j]-a[i];
	 
	 if(csum>msum)
	 {
		 msum=csum;
	 }
	}
	

}
if(msum<a[n-1])
msum=a[n-1];
    cout<<msum<<endl; 
	t--;
	
}

return 0;

}

#2

hello @amangupta
u r getting run error because
a) u are accessing negative index.

b) ur array size is small , value of n can be upto 100000 , so ur array size should be atleast 100000
image

#3

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#4

Hey,you have taken a[-1]=0 which is wrong.You can’t access -ve index.
Runtime error genrally occurs when for some input there is some memory access which is not defined or an infinite loop.