How to Perform Various Operations on a Stack
How can we set i to the second element from the top of the stack and remove the top two elements?
a. Use two pop operations and a stacktop operation
b. Use a loop to remove the top two elements
How can we set i to the second element from the top of the stack without changing the stack?
a. Use stacktop and push operations
b. Use a helper function to keep track of elements
Answer:
This answer provides pseudo-code operations using push, pop, stacktop, and empty to perform various operations on a stack.
1. To set i to the second element from the top of the stack and remove the top two elements, you can use the pop operation twice and then use the stacktop operation to get the value of i.
2. To set i to the second element from the top of the stack without changing the stack, you can use the stacktop and push operations to temporarily store the top element, then remove and restore the top element of the stack.