Stacks

a) For each of the following stack operations, fill in the chart below. Also assuming the return value of each call to size(), top(), and empty() is sent to the screen, what is the output? (If there is nothing in the stack top() and pop() print error.). The first two are done for you.

Operation	Output	Stack Contents
push(5)	--	(5)
push(7)	--	(7,5)
push(5)
push(22)
push(15)
size()
empty()
pop()
pop()
top()
top()
push(17)
top()
pop()
pop()
pop()
empty()
pop()
pop()
empty()
pop()
empty()

b) Given the class ArrayStack, write a full program that would take in an arbitrary string of parentheses, curly braces, and square braces, and outputs if the string is balanced or not. The string is said to be balanced if all opening elements have a matching closing element of the same type. e.g. The string ( [ ] { } { } { ( ) } ) would be considered balanced, but ( { ) [ ( ] ) ) would not. Refer to Section 5.1.7 (pg 204-205) in your textbook for the algorithm.

Answer:

#include

#include

#include "ArrayStack.h"

int main( ) {

// set up the stack, string, and flag variables

ArrayStack checker;

string input = "";

bool unbalanced = false;

// get the string

cin >> input;

// run through the loop

for (int i =0; i < input.length() && !unbalanced; i++) {

// Your code goes here.

}

// report to the user

cout << "The string is " << (unbalanced ? "unbalanced" : "balanced") << endl;

return 0;

}