This is a JSFiddle Assignment so this needs to be written at

This is a JSFiddle Assignment so this needs to be written at jsfiddle.net with the HTML and Java scriptincluded

Implement a Stack in Javascript. Do not use an array as the stack or in the implementation of the stack. Repeat - You MUST implement the Stack (start with your linked list) without the use of an array..

When a number is entered it goes onto the top of the stack. When an operation is entered, the previous 2 numbers are operated on by the operation and the result is pushed onto the top of the stack. This is how an RPN calculator.

For example

6 [enter] 6

2 [enter] 2 6

* [enter] * 2 6 -> collapses to 12

would leave at 12 at the top of the stack.

The program should use a simple input box, either a text field or prompt and display the contents of the Stack.

Solution

Since we are restricted from using an Array, we\'ll use the DOM itself to store the values and make it work like a stack.


HTML
<input type=\'text\' id=\'val\'/>
<input type=\'button\' value=\'Submit\' onclick=\'fun()\'/>
<br/>
Current Stack:&nbsp;
<div id=\'CurrentStack\'>
</div>

JAVASCRIPT
function fun() {
       var data = document.getElementById(\"val\").value;
updateCurrentStack(data);
}
function updateCurrentStack(data){
       switch(data){
case \'+\':
   pushToStack(parseInt(popFromStack()) + parseInt(popFromStack()));
   break;
case \'-\':
   pushToStack(parseInt(popFromStack()) - parseInt(popFromStack()));
   break;
case \'*\':
   pushToStack(parseInt(popFromStack()) * parseInt(popFromStack()));
   break;
case \'/\':
   pushToStack(parseInt(popFromStack()) / parseInt(popFromStack()));
   break;
default:
           pushToStack(data);
}
}
function pushToStack(data){
   document.getElementById(\"CurrentStack\").innerHTML += data + \" \";
document.getElementById(\"val\").value = \"\";
}
function popFromStack(){
   var stack = document.getElementById(\"CurrentStack\").innerHTML;
document.getElementById(\"CurrentStack\").innerHTML = \"\";
var res = stack.split(\" \");
for(var i=0;i<res.length-2;i++)
   document.getElementById(\"CurrentStack\").innerHTML += res[i] + \" \";
document.getElementById(\"val\").value = \"\";
return res[res.length-2];
}