hackerrank-solutions/Day9.BinaryCalculator.js at master · TheNewStyles/hackerrank-solutions · GitHub

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// Objective

// In this challenge, we implement a calculator that uses binary numbers. Check out the attached tutorial for learning materials.

// Task

// Implement a simple calculator that performs the following operations on binary numbers: addition, subtraction, multiplication, and division. Note that division operation must be integer division only; for example, , , and .

// The calculator's initial state must look like this:

// image

// Element IDs. Each element in the document must have an id, specified below:

// innerHTML	id	Description/Behavior
// res	Contains the result of button presses.
// btns	A button container that displays all eight calculator buttons.
// 0	btn0	A button expressing binary digit .
// 1	btn1	A button expressing binary digit .
// C	btnClr	A button to clear the contents of .
// =	btnEql	A button to evaluate the contents of the expression in .
// +	btnSum	A button for the addition operation.
// -	btnSub	A button for the subtraction operation.
// *	btnMul	A button for the multiplication operation.
// /	btnDiv	A button for the integer division operation.
// Styling. The document's elements must have the following styles:

// body has a width of 33%.
// res has a background-color of lightgray, a border that is solid, a height of 48px, and a font-size of 20px.
// btn0 and btn1 have a background-color of lightgreen and a color of brown.
// btnClr and btnEql have a background-color of darkgreen and a color of white.
// btnSum, btnSub, btnMul, and btnDiv have a background-color of black, a color of red.
// All the buttons in btns have a width of 25%, a height of 36px, a font-size of 18px, margin of 0px, and float value left.
// The .js and .css files are in different directories, so use the link tag to provide the CSS file path and the script tag to provide the JS file path:

// <!DOCTYPE html>
// <html>
//     <head>
//         <link rel="stylesheet" href="css/binaryCalculator.css" type="text/css">
//     </head>

//     <body>
//     	<script src="js/binaryCalculator.js" type="text/javascript"></script>
//     </body>
// </html>
// Constraints

// All expressions in the test dataset are entered in the form , where  is the first binary number,  is the second binary number, and  is in the set .
// Both operands will always be positive integers when converted from base- to base-.
// All expressions will be valid.
// Explanation

// Consider the following sequence of button clicks:

// Before pressing the  button, the result div looks like this:

// 27+8

// After pressing the  button to evaluate our expression, the result div looks like this:

// 27+8eval

// Notice that , , and , so our calculator evaluated the expression correctly.

// Now, let's consider our next sequence of button clicks as:

// Before pressing the  button, the result div looks like this:

// 141x7

// After pressing the  button to evaluate our expression, the result div looks like this:

// 141x7eval

// Consider the next sequence of button clicks as:

// The result div looks like this:

// clear3

btn0.onclick = function () {
    res.innerHTML += 0;
 };

 btn1.onclick = function () {
   res.innerHTML += 1;
 };

 btnClr.onclick = function () {
   res.innerHTML = '';
 };

 btnSum.onclick = function () {
     if (!re(res.innerHTML)) {
         res.innerHTML += '+';
     }
 }

 btnSub.onclick = function () {
     if (!re(res.innerHTML)) {
         res.innerHTML += '-';
     }
 }

 btnMul.onclick = function () {
     if (!re(res.innerHTML)) {
         res.innerHTML += '*';
     }
 }

 btnDiv.onclick = function () {
     if (!re(res.innerHTML)) {
         res.innerHTML += '/';
     }
 }

 btnEql.onclick = function () {
     let resString = res.innerHTML;
     let operands = getOperands(resString);
     if (operands.length < 2) {
         return;
     }
     let operator = getOperator(resString);
     let parsed = eval(parseInt(operands[0], 2) + operator + parseInt(operands[1], 2));
     parsed = Math.floor(parsed);
     res.innerHTML = parsed.toString(2);
 }

 let getOperator = function (string) {
     const regex = /[^-+*/]/g;
     return string.split(regex).join('');
 }

 let getOperands = function (string) {
     const regex = /[-+*/]/g;
     return string.split(regex).filter(String);
 }

 let re = function (string) {
     const regex = /[-+*/]/g;
     if (regex.test(string) || res.innerHTML === '') {
         return true;
     }
 }