How to check if certain position in array is modified using pointers

I don't understand how I can check if a certain position in an array is been modified or not. Below is an example:

int array[5];

array[2] = 23;
array[4] = 23;

for (int i = 0; i < 5; ++i) {
    if (array[i] == ????){
        cout << "in array";
    } else {
        cout << "not in array";
    }
}

So I wanted to know how would I get it so the if statement is checking if the item has been modified. So once I becomes 2 it will says it's in array and if not the it should print 'not in array'.

This has to be done using pointers.