Unable to understand Comparator function behaviour when sorting an array of 1000 elements with value 1000000 in descending order. (The array is 1 indexed)

help
1

The first instance of definition of comparator function has random zeroes at some indexes in the array.

The second instance of definition of comparator function works fine. Could anyone explain why this is happening

bool func(long long a, long long b){
return (a >= b);
}

sort (A+1, A + 1000 + 1, func);

bool func(long long a, long long b){
return (a > b);
}

sort (A+1, A + 1000 + 1, func);

Output 1:
1000000 1000000 1000000 0 0 1000000 1000000 1000000 1000000 1000000 1000000 1000000 1000000 1000000 1000000 1000000 1000000 1000000 1000000 1000000 1000000

Output 2:
1000000 1000000 1000000 1000000 1000000 1000000 1000000 1000000 1000000 1000000 1000000 1000000 1000000 1000000 1000000 1000000 1000000 1000000 1000000 1000000 1000000