How could a key could be inserted in a heap without increasing the size of an array?


MAX-HEAP-INSERT(A, key)     A.heap-size = A.heap-size + 1     A[A.heap-size] = -infinity     HEAP-INCREASE-KEY(A,A.heap-size,key) 

How could a key could be inserted in a heap without increasing the size of an array? With this code from Introduction To Algorithms, you can’t just randomly increase the heap size upon wish. Did I miss something? All all online lectures I have seen do no talk about this issue. Neither does the book touch this issue. Or is it that the lowest key in an array would be dropped automatically?