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Asked: 2 years agoIn:
Teacher

I’m having a bit of trouble understanding how to use a null statement in my programming code. I’ve been working on building a website where the user inputs some data and then the website performs some calculations and spits out ...Read more

I’m having a bit of trouble understanding how to use a null statement in my programming code. I’ve been working on building a website where the user inputs some data and then the website performs some calculations and spits out an answer. I’m using JavaScript as the language for this particular part of the site, and I’ve seen some code samples online that use the null statement.
Here’s an example of what I’m trying to do:

function calculateAnswer() {
var input1 = parseInt(document.getElementById("input1").value);
var input2 = parseInt(document.getElementById("input2").value);
var answer;

if (input1 < input2) { answer = input2 - input1; } else if (input1 > input2) {
answer = input1 - input2;
}
// what goes here?
document.getElementById("result").innerHTML = answer;
}

In the code above, the if and else if statements work perfectly fine. The problem arises when both input1 and input2 are equal – I want the “answer” variable to be set to null in that case. But I’m not sure how to do that. I’ve seen some people use a single semicolon as the null statement, but I don’t understand why that works. Could someone explain how to use a null statement in JavaScript code, and perhaps give an example of when it might be necessary? Thank you in advance!

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coding-conceptscoding-problemsnull-statementprogramming-basicssyntax
  1. norolahian Begginer

    In programming, a null statement is a statement that has no effect on the program execution. This statement is used to keep track of the program flow and to add a placeholder for future instructions. An example of a null statement is the empty statement, which is written as a semicolon (;). This staRead more

    In programming, a null statement is a statement that has no effect on the program execution. This statement is used to keep track of the program flow and to add a placeholder for future instructions. An example of a null statement is the empty statement, which is written as a semicolon (;). This statement can be used when a loop or an if statement does not need to execute any code after the condition is tested.

    Imagine you are creating an if statement that checks if a user entered a valid input. If the input is invalid, you want to display an error message and prompt the user again until the input is valid. In this case, you can use a null statement to indicate that there is no code to execute when the input is valid. This will keep the program flow intact while waiting for valid input. Without the null statement, the program would terminate when the input is valid, which is not what you want.

    Using null statements is a common practice in programming and helps you to write efficient and maintainable code. By using null statements, you can write code that is self-documenting and easy to understand for future developers who may need to work on your code. So, don’t be afraid to use null statements in your code where appropriate, as it can help to make your code more efficient and robust.

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Asked: 3 years agoIn:
Teacher

I am working on a Python class for my web development project, and I am stuck at a strange error. I have a class `User` which has an attribute `username`. I am trying to create a class method `get_user_by_username` which ...Read more

I am working on a Python class for my web development project, and I am stuck at a strange error. I have a class `User` which has an attribute `username`. I am trying to create a class method `get_user_by_username` which takes in a username as an argument and returns an instance of the `User` class with that username. Here’s my code:

class User:
def __init__(self, username):
self.username = username
@classmethod
def get_user_by_username(cls, username):
return cls(username)

Now, when I try to create a new user instance and call the `get_user_by_username` method, it throws me an error saying `TypeError: get_user_by_username() missing 1 required positional argument: ‘username’`. Here’s my code:

user1 = User('John')
user2 = User.get_user_by_username()

I am not sure what I am doing wrong here. I am passing the `username` argument to the `User` class constructor while creating a new instance, and it works perfectly fine. But when I try to call the `get_user_by_username` method, it expects me to pass the `username` argument again, even though I am calling it on the class itself. Can anyone help me fix this error and implement the `get_user_by_username` method properly? Thank you in advance.

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attributesclassinheritancemethodsOOPpythonsyntax
  1. utxpiv_ Begginer

    The error "libpng warning iccp known incorrect sRGB profile" usually occurs when an image has an incorrect profile. To resolve this issue, open the image using a photo editing software and make sure it is saved without any color profile or with a proper sRGB color profile. Sometimes this error is alRead more

    The error “libpng warning iccp known incorrect sRGB profile” usually occurs when an image has an incorrect profile. To resolve this issue, open the image using a photo editing software and make sure it is saved without any color profile or with a proper sRGB color profile.
    Sometimes this error is also generated because the image is missing a profile, so to fix this, you can set the color profile of your image before saving it. This can be done using a photo editing software or command-line tools like ImageMagick.
    In my personal experience, I had encountered this error while working on a web project. I had to make sure that all the images used on my website were optimized and saved with the correct color profile. This helps in reducing the page load time while maintaining the color quality of the images.
    To troubleshoot this error, it is also recommended to check if your code is properly handling the image files and loading them in the correct format. Sometimes, the issue may not be with the image itself but with the way it is being processed and loaded. By following these steps and practices, you can avoid this error and ensure that all the images on your website or application are displayed correctly.

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    • 30
Asked: 6 years agoIn:
Begginer

I’m trying to create a conditional loop with outputs in my code, but I seem to be missing something. Here is a simplified version of what I currently have: function printNumbers(){ let numArr = [1, 2, 3, ...Read more

I’m trying to create a conditional loop with outputs in my code, but I seem to be missing something. Here is a simplified version of what I currently have:

function printNumbers(){
let numArr = [1, 2, 3, 4, 5];
for(let i=0; i
This code works as expected and outputs the numbers 1-5 along with whether they are odd or even. However, what I want to do is add a condition where, if the number is even, it also outputs the next number in the array. So for example, the output would be "2 is even, the next number is 3" for the number 2.
I've tried adding another if statement inside the existing one like this:

function printNumbers(){
let numArr = [1, 2, 3, 4, 5];
for(let i=0; i
But now the output shows the next number for every even number, even if it's the last number in the array. How can I modify my code to only show the next number for even numbers that aren't the last? Any help would be greatly appreciated!

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codeconditional loopoutputprogrammingsyntax
  1. utxpiv_ Begginer

    The error "libpng warning iccp known incorrect sRGB profile" usually occurs when an image has an incorrect profile. To resolve this issue, open the image using a photo editing software and make sure it is saved without any color profile or with a proper sRGB color profile. Sometimes this error is alRead more

    The error “libpng warning iccp known incorrect sRGB profile” usually occurs when an image has an incorrect profile. To resolve this issue, open the image using a photo editing software and make sure it is saved without any color profile or with a proper sRGB color profile.
    Sometimes this error is also generated because the image is missing a profile, so to fix this, you can set the color profile of your image before saving it. This can be done using a photo editing software or command-line tools like ImageMagick.
    In my personal experience, I had encountered this error while working on a web project. I had to make sure that all the images used on my website were optimized and saved with the correct color profile. This helps in reducing the page load time while maintaining the color quality of the images.
    To troubleshoot this error, it is also recommended to check if your code is properly handling the image files and loading them in the correct format. Sometimes, the issue may not be with the image itself but with the way it is being processed and loaded. By following these steps and practices, you can avoid this error and ensure that all the images on your website or application are displayed correctly.

    See less
    • 30