Q26.cpp

/*
Aledutron
SPPU 2019 SE DSL Lab
SPPU Computer Engineering Second Year (SE) Data Structure Lab (DSL) / Fundamentals of Data Structures (FDS) Assignments (2019 Pattern)
Youtube DSL / FDS Playlist Link: https://youtube.com/playlist?list=PLlShVH4JA0osUGQB95eJ8h5bTTzJO89vz&si=u12IYwo93Z7RU4e8

Problem Statement:
Group-D\Q26.cpp
In any language program mostly syntax error occurs due to unbalancing delimiter such as (),{},[]. Write C++ program using stack to check whether given expression is well parenthesized or not.

Explaination Video Link: https://www.youtube.com/watch?v=265DLjJRuG8&list=PLlShVH4JA0osUGQB95eJ8h5bTTzJO89vz&index=13&pp=iAQB
*/

#include <iostream>
using namespace std;

class Stack
{
public:
	const static int size = 100;
	int top = -1;
	char array[size];

	void push(char x)
	{
		if (top == size - 1)
		{
			cout << "Stack Overflow!!";
			return;
		}

		array[++top] = x;
	}

	char pop()
	{
		if (top == -1)
		{
			cout << "Stack Underflow!!";
			return -1;
		}

		return array[top--];
	}

	void display()
	{
		if (top == -1)
		{
			cout << "Stack is Empty";
		}

		cout << "Stack contains: ";
		for (int i = 0; i <= top; i++)
		{
			cout << array[i] << " ";
		}
		cout << endl;
	}

	char peek()
	{
		return array[top];
	}

	bool isEmpty()
	{
		if (top == -1)
		{
			return 1;
		}
		else
		{
			return 0;
		}
	}
};

int main()
{
	Stack brackets;
	string s;
	cout << "Enter the parenthesis to check balancing: ";
	cin >> s;

	bool is_balanced = true;

	for (int i = 0; i < s.size(); i++)
	{

		if (s[i] == '(' or s[i] == '{' or s[i] == '[')
		{
			brackets.push(s[i]);
		}

		else if (s[i] == ')' or s[i] == '}' or s[i] == ']')
		{

			if (brackets.isEmpty())
			{
				is_balanced = false;
				break;
			}

			char last_bracket = brackets.peek();

			if (s[i] == ')' and last_bracket == '(')
			{
				brackets.pop();
			}
			else if (s[i] == '}' and last_bracket == '{')
			{
				brackets.pop();
			}
			else if (s[i] == ']' and last_bracket == '[')
			{
				brackets.pop();
			}
		}
	}

	if (not brackets.isEmpty())
	{
		is_balanced = false;
	}

	if (is_balanced)
		cout << s << " is balanced." << endl;
	else
		cout << s << " is not balanced." << endl;
}