Write a method called switchPairs that accepts a stack of integers as a
parameter and swaps neighboring pairs of numbers starting at the
bottom of the stack. For example, if the stack initially stores [1, 2, 8,
6, 21, 15, 7], your method should swap the first pair (1, 2), the
second pair (8, 6), the third pair (21, 15), and so on. If the stack contains
an odd number of elements, the element at the top should remain
unmodified. So the final state of the stack would be [2, 1, 6, 8, 15,
−1, 7]. Use one queue as auxiliary storage.
10. Write a method called isConsecutive that accepts a stack of integers as
a parameter and that returns true if the stack contains a sequence of
consecutive integers starting from the bottom of the stack. Consecutive
integers are integers that come one after the other, as in 3, 4, 5, etc. If the
stack stores [5, 6, 7, 8, 9, 10], your method should return true. If
the stack had instead contained [7, 8, 9, 10, 12], your method
should return false because the numbers 10 and 12 are not consecutive.
Notice that we look at the numbers starting at the bottom of the stack.
Any stack with fewer than two values should be considered to be a list
of consecutive integers. Your method must restore the parameter stack
to its original state before returning. Use one queue as auxiliary storage.