C#

Question

using System;
using System.Text;

namespace Stack_Implementation
{
    class Node
    {
        public int info;
        public Node next;
        public Node(int i, Node n)
        {
            info = i;
            next = n;
        }
    }

    class Stacks
    {

        Node top;

        public Stacks()
        {
            top = null;
        }

        bool empty()
        {
            if (top == null)
                return (true);
            else
                return (false);
        }

        public void push(int element)
        {
            Node fresh;
            fresh = new Node(element, null);

            fresh.next = top;
            top = fresh;
            Console.WriteLine("\n" + element + " pushed.");
        }

        public void pop()
        {
            Console.WriteLine("\nThe popped element is: " + top.info);
            top = top.next; //Make top point to the next node in sequence
        }

        public void display()
        {
            Node tmp;
            if (empty())    //If stack is empty
                Console.WriteLine("\nStack Empty");
            else
            {
                //Traverse the list from begginning till end
                for (tmp = top; tmp != null; tmp = tmp.next)
                {
                    Console.WriteLine(tmp.info);
                }
                Console.WriteLine();
            }
        }
        static void Main(string[] args)
        {
            Stacks s = new Stacks();
            while (true)
            {
                Console.WriteLine();
                Console.WriteLine("\n***Stack Menu***\n");
                Console.WriteLine("1. Push.");
                Console.WriteLine("2. Pop");
                Console.WriteLine("3. Display");
                Console.WriteLine("4. Exit");

                Console.Write("\nEnter your choice: ");

                string sInput = Console.ReadLine();

                char ch = Convert.ToChar(sInput == "" ? "0" : sInput);
                switch (ch)
                {
                    case '1':
                        Console.Write("\nEnter a number: ");
                        int num = Convert.ToInt32(Console.ReadLine());
                        s.push(num);
                        break;
                    case '2':
                        if (s.empty())
                        {
                            Console.WriteLine("\nStack Empty");
                            break;
                        }
                        s.pop();
                        break;
                    case '3':
                        s.display();
                        break;
                    case '4':
                        return;
                    default:
                        Console.WriteLine("\nInvalid Choice");
                        break;

                }
            }
        }
    }
}

 What is the use of ? symbol in Stack in  c sharp

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Ashish

Answer 1

sInput == "" ? "0" : sInput

? is to check whether the condition (sInput == "") is true or false. If it is true the statement will return "0" else it will return sInput.

The above code is a shorthand version of if/else condition.

if(sInput == "" )
{
   return "0";
}
else
{
   return sInput;
}

Hope you understand.

Parth

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Answer 2

 Hi 

   It's just like conditional stmts  if ...else 

      sInput == "" ? "0" : sInput

  if (sInput=="") then 0 else sInput

Answer 3

Thanku..........................................

---

Ashish