How to count the entries of array while taking them as an input from the user?

[sabbag learner]

Hi!
I have understand arrays a little bit. But the problem, I am dealing with requires to count the entries when they are entered by the user , which then defines the size of array. The problem then demands to find the sum and average.
I have made the code as per my knowledge.But it's not working.
Help!

#include<iostream>
using namespace std;
int main()
{
int i, count;
double grade[count] ,average,sum;
for(i=0;grade[i]>=0;i++)
{ if(grade[i]>=0)
{
cout<<"Grade "<<i+1<<": ";
cout<<grade[i];
count++;
}
else
break;
}
for(i=0,sum=0;i<count;i++)
{
sum=sum+grade[i];
}
average=sum/count;

cout<<"Average"<<average;
}

[Moschops]

double grade[count]

Here, I see you are making an array. Tell me, what is the size of this array?

[sabbag learner]

The size of Array is making trouble. The problem states:"... reads a list of double-precision
grades from the keyboard into an array named grade. The grades are to be counted as they’re
read, and entry is to be terminated when a negative value has been entered."
So here what I understand is The size of arrays will be determined by the number of entries.

[Moschops]

Yes you're trying to create the array BEFORE you know how big it needs to be. Do you see a problem there? Do you understand that you need to know how big to make an array before you make it?

[sabbag learner]

So what is the solution. How I am suppose to take a size of array when it is not mentioned?

[Moschops]

Make a big array. If it turns out not to be big enough, make a bigger array, copy the first one into the second, and then keep going.

This is something you could have worked out for yourself. Programming is thinking.

[sabbag learner]

Yeah programming is Thinking. But it usually fails when you got exam next day . Thanks anyway.