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JavaScript The Solution

Russell Smitheram
Russell Smitheram
2,009 Points
Posted by Russell Smitheram
Russell Smitheram
2,009 Points

I solved the challenge but did I do it a long winded way?

I gave this challenge a shot and solved it but I feel I've done it a really long winded way.

Can anyone have a look and give me some feedback please?

Workspace snapshot - https://w.trhou.se/ypgwqlrl3k

I added the console.log() to the beginning and end to help with debugging as I went.

6 Answers

Steven Parker
Steven Parker
231,184 Points
Steven Parker
Steven Parker
231,184 Points

Your program seems quite compact as it is. You could split up the assignment of "message" into several smaller statements to have shorter lines (but more of them). Or you could employ functions to change the program structure,. But neither of these would significantly condense this program.

These would be good techniques to apply to larger programs, and you'll see examples of both as you continue with the courses.

Steven Parker
Steven Parker
231,184 Points
Steven Parker
Steven Parker
231,184 Points

Since there seems to be continued interest, here's an example implementing my function suggestion:

alert(`Let's do some math!`);
const num1 = prompt("Please type a number");
const num2 = prompt("Please type another number");
const calc = op => `${num1} ${op} ${num2} = ${eval(num1+op+num2)}<br>`;

document.writeln(
  `<h1>Math with the numbers ${num1} and ${num2}</h1><br>` +
    calc("+") + calc("*") + calc("/") + calc("-")
);

:warning: Warning: for demonstration only — using "eval" on user inputs is a big security vulnerability!

kaganulucay
seal-mask
.a{fill-rule:evenodd;}techdegree
kaganulucay
Full Stack JavaScript Techdegree Student 16,491 Points
kaganulucay
.a{fill-rule:evenodd;}techdegree
kaganulucay
Full Stack JavaScript Techdegree Student 16,491 Points

Here is the more compact way just take a look

alert(`Let's do some math!`);
const number1 = prompt('Please type a number');
const number2 = prompt('Please type another number');

document.writeln(`
    <h1>Math with the numbers ${number1} and ${number2}</h1><br>
    ${number1} + ${number2} = ${number1 + number2}<br>
    ${number1} * ${number2} = ${number1 * number2}<br>
    ${number1} / ${number2} = ${number1 / number2}<br>
    ${number1} - ${number2} = ${number1 - number2}<br>
`)
Steven Parker
Steven Parker
231,184 Points
Steven Parker
Steven Parker
231,184 Points

Compact, yes, but without the numeric conversions, the "+" operator performs concatenation on the two strings.

"2 + 3 = 23" :smirk:

kaganulucay
.a{fill-rule:evenodd;}techdegree
kaganulucay
Full Stack JavaScript Techdegree Student 16,491 Points

Okay so here you go:

alert(`Let's do some math!`);
const number1 = prompt('Please type a number');
const number2 = prompt('Please type another number');

calculation = (number1,number2) => {
    document.writeln(`
    <h1>Math with the numbers ${number1} and ${number2}</h1><br>
    ${number1} + ${number2} = ${number1 + number2}<br>
    ${number1} * ${number2} = ${number1 * number2}<br>
    ${number1} / ${number2} = ${number1 / number2}<br>
    ${number1} - ${number2} = ${number1 - number2}<br>
`)
}

if(number1 == 0 || number2 == 0){
    alert(`You can't divide by zero. Reload and try again.`);
}
else if(isNaN(number1) == true || isNaN(number2) == true){
    alert(`At least one of the values you typed is not a number. Reload and try again.`)
}
else{
    calculation(number1,number2);
}
Steven Parker
Steven Parker
231,184 Points
Steven Parker
Steven Parker
231,184 Points

I see you added some error checking, but the situation I was pointing out occurs with normal inputs. For example, if the numbers 2 and 3 are entered, you'll get: "2 + 3 = 23". The revised code performs the same in that regard.

But in itself, sanity checking on user inputs is always a good idea for deployed code. :+1:

And I posted a comment to my original answer with an example using a function.

kaganulucay
.a{fill-rule:evenodd;}techdegree
kaganulucay
Full Stack JavaScript Techdegree Student 16,491 Points

Oh so I would probably use Number() function

 ${number1} + ${number2} = ${Number(number1) + Number(number2)}

Something like this. Or I would apply that when I prompt the number.

const number1 = Number(prompt('Please type a number'));
const number2 = Number(prompt('Please type another number'));
Steven Parker
Steven Parker
231,184 Points
Steven Parker
Steven Parker
231,184 Points

There ya go. Either that or "parseFloat" as Russell had and you're good.

Russell Smitheram
Russell Smitheram
2,009 Points
Russell Smitheram
Russell Smitheram
2,009 Points

Thank you for your reply, Steven. Much appreciated.

Curtis Chadwell
Curtis Chadwell
3,150 Points
Curtis Chadwell
Curtis Chadwell
3,150 Points

I did it the same way to help me read it better.

alert('Math Time!'); var firstNum = prompt('What is your first number?'); firstNum = parseFloat(firstNum); var secondNum = prompt('What is your second number?'); secondNum = parseFloat(secondNum); var addNums = firstNum + secondNum; var subNums = firstNum - secondNum; var mulNums = firstNum * secondNum; var divNums = firstNum / secondNum;

var message = '<h1>Math with the numbers ' + firstNum + ' and ' + secondNum + '</h1><br>'; message += firstNum + ' + ' + secondNum +' = ' + addNums; message += '<br>'; message += firstNum + ' * ' + secondNum + ' = ' + mulNums; message += '<br>'; message += firstNum + ' / ' + secondNum + ' = ' + divNums; message += '<br>'; message += firstNum + ' - ' + secondNum +' = ' + subNums;

document.write(message);

Steven Parker
Steven Parker
231,184 Points
Steven Parker
Steven Parker
231,184 Points

To make your code look better, use the instructions for code formatting in the Markdown Cheatsheet pop-up below the "Add an Answer" area. :arrow_heading_down:   Or watch this video on code formatting.

You could also make a snapshot of your workspace and post the link to it here, as Russell did.

Curtis Chadwell
Curtis Chadwell
3,150 Points
Curtis Chadwell
Curtis Chadwell
3,150 Points

I copy and pasted from a different editor, and it looked like that after I submitted it. It was clear before.

Steven Parker
Steven Parker
231,184 Points
Steven Parker
Steven Parker
231,184 Points

Sure, it changes when you post it in the forum because the forum is processing the posts with "Markdown".

Curtis Chadwell
Curtis Chadwell
3,150 Points
Curtis Chadwell
Curtis Chadwell
3,150 Points

I see, thanks

Steven Parker
Steven Parker
231,184 Points
Steven Parker
Steven Parker
231,184 Points

Try using one of my suggestions to edit your code above to make it appear correctly.