Designing Accurate data Entry Procedures

Here's the transcript arranged with proper punctuation:

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Before you are... a bit like this. I am coming now, in front of Allah.

Sir: Assalamu Alaikum.
Talking: Yes, ma'am. Can't you see the screen?
Mam: Is the screen showing fine?
I: Ok, we start.

In the last class, what we were looking at was how we can create an effective interface for my system. So, for that, we were looking at some points, keeping in mind some things we need to design our interfaces.

What we are going to do today is quality assurance. Are you done? Whether you can maintain the quality of it. What does it mean? Evaluation—whether your work is done correctly.

The name of this chapter is "Designing Accurate Data Entry Procedures." Now let's come to the data entry procedure. You can understand very well that the output of the system you are building will depend on its input. If you give wrong inputs, then the output will be wrong. So, what will be the inputs for your system now?

It is the job of a system analyst to determine which inputs to call correct inputs. No? Then, there is no point in arguing with the user. What should be done? The system should be designed according to the user's requirements. The system should provide all the inputs required. If you can't, then your system can't ensure quality. Well, now let's come to a term that is effective coding.

Well, before reading this, we will remember two terms very well. One is "effective," and the other is "efficient." Are they the same thing? Effective and efficient are two completely different things. The terms have different meanings. I am defining the two from our scope of study.

Can't answer the question? You can answer well; if you can answer it correctly, that is effective answering. The task you can do well is an effective task. You know, efficient work, effective and efficient are two completely different things.

While working efficiently, even if you do the work properly, if you do not do it timely, the work will not be effective. While working effectively, if you cannot measure time, the work will not be efficient. So, to do any work effectively and efficiently, you must maintain the quality of the work. Plus, the timing of the work—you have to judge what is the maximum output I can give in this time. This is the difference between effectiveness and efficiency, so keep this in mind during the exam so that you don't get confused between these two.

Now we come to effective coding. Effective word meaning—I understood well to complete a task. What does coding mean? Giving a name to a thing, giving a code name. In the last class, I gave an example: Suppose you want to book a plane flight. You want to book the flight from Dhaka Airport. If you are going to book the ticket by using only the airport code, without writing the entire "International Airport," then the Dhaka airport code that you will input is the effective coding here. It means how well you can set the code of a particular name.

Now, what is the purpose of code setting? What are the five purposes of keeping track of something, classifying information, concealing information, revealing information, and requesting appropriate action? Let's do the first point: keeping track of something. Well, what does that mean? I can use a product code to keep track of that product. Businessmen, okay? So many transactions are happening daily in your business, so you want to keep track of the transactions. What kind of transactions are you having every day? What kind of transactions are happening every month?

What you have to do to keep track of these transactions: You have to remember what transactions are happening every day, right? You have to count and see if it happened today, if it happened tomorrow, then I am doing the sum. But if you set a code in the agent of each transaction, then the code will automatically be incremented by one in the next transaction. Then, at the end of the day, you can only see the incremented sum or the increment number and say how many transactions you have today. By assigning a code like this, you can keep track of any product, transaction, or work very easily.

Now, what can the codes be? There is a simple sequence code—number, then number two, then number three, then another one like this. There can be alphabetic derivation codes. Alphabetic derivation codes—what does alphabetic derivation codes mean? Look at the example. What is the code driving through any place? Then you can easily understand the meaning of this code.

For example, the first five digits are the first five digits from the left-hand side. That digit is the zip code of an area. The next three letters are correct. The consonant of a person's first name is correct. Then the next four letters are the street address on which the person lives. The next three letters are the abbreviation of the magazine he wants to subscribe to. Then, if you are a magazine delivery boy or a newspaper delivery boy, you need this code. You can easily deliver the magazine that he is subscribing to at this address. You don't need to write so many things in detail.

Only through a unique code can you easily send a person his home address and all the information, including which magazine he is subscribing to. You're getting the advantage of the code in that you can keep track of things like that, and you can incorporate a lot of information into a very small piece of code.

You can read the next point. Next point means the next point of purpose: classifying. Classifying means classification. Classification means dividing. It means I have a lot of information. I will divide the information into different parts. Now it will be easy to divide it if the information is in the form of a code. How do you think you are logging into a website? Well, many types of people can log into a website.

So, when you log in, you are logging in by saying your gender is male or female. After studying about it, he will be able to classify what percentage of the users of his website are male and what percentage are female. This is what I classified.

I have given an example. If I give another example, what other examples can be given? Well, suppose I am using your Twitter website. How many percent of teachers are using it? How many percent of students are using it? You can arrange the codes in these different ways. Now, if someone wants to log in as a teacher, he can use this code only without writing his identification as a teacher. He must mention the teacher; he means by the teacher on the website. If you select the "T" block, it will go to the teacher category. Now, when you see that there are so many percent of teachers in the "T" category, you can easily classify the users of your website by code.

Now, look at the code for interest payment. "I" is the code for medical payments. "M" is for tax, "T" is for contributions, "C" is for dues, "D" is for supplies. This is an example: For your different items or for different products, you can set the code differently.

Ok, now if you determine the code with the first letter of the first letter or the first alphabet, is there any problem with it? Do you think there is a problem? If so, then there will not be one created here that the "I" code means interest payment, not any other interest. In that case, finding such a first alphabet is not feasible. You can do the numbering without giving the first alphabet.

First two letters can be coded in many ways. It depends on you, but the codes have to be done in such a way that there is no ambiguity. See, for example, an interest payment code "I" is also an insurance code "I." Now, what can you do in that case? You use the second letter. You can justify the insurance by doing this.

Now, what is the problem when you do this? Do you have to remember who you mean by so many letters? So, you have to devise a unique coding system so that you don't have to change different rules for such a unique one. The system will give you a unique code for each item so that you can read the codes to understand that it is interest payment, it is medical payment, it is clear, it is past, it is next.

It is block sequence code. Block sequence code—block means I have a pile of items; it is a block, and sequence means items. They are in the form of sequences. Now, can you give an example? Suppose you have a list of many computer software. Now, number one has it, number two has it, and number three. You can write it serially like this. In that case, you will have no orientation in it. If you organize it a little bit more, how can you do it? You can divide all the computer software you have into one category. For example, some software is used as browsers, some are used as databases, and some can be used for your web design.

You keep those software in separate blocks—the browser for a block, the database for a block, and web design for a block. Then you will sequence inside a block. This is called block sequence code. Only the sequence code—if one, two, three—you write the names of the serial by software. That is, the sequence code is in number one, it is in number two, it is in number three. The block sequence code first divides each item into blocks. Similar kinds of items will be in a block. Then you will sequence one, two, three within that block.

Ok, see the example. The codes that start with "1" are the codes of the browser. The codes that start with "2" are of

 the database. Codes that start with "3" are for web design. "10" is Apple Safari, "101" is Mozilla Firefox, "102" is Internet Explorer. This is how you sequence inside a block. This is the block sequence code.

Then, concealing information. We remember the purpose of effective coding. These purposes—one by one, we are looking at the example of how the coding can be. Clear? Well, concealing information. Understood. There is a need for the code. I want to share some data with you that no one but you and I will understand. Okay, so what do we do? I will develop the code in that coding language. I will tell you what happened, but neither you nor I can understand our words. We are keeping my information confidential from the third person.

Ok, now an example of this is cipher code. Cipher code—you all know this. I am a little light. Let's say the cipher code is: I will tell you a sentence. I am encoding that sentence by replacing each of the letters in that sentence with another letter. You won't understand because I know I replaced it with "A," and I replaced it with "E." OK, "B," I replaced it with "F." So, if I send it to you like this, will you understand? You won't. Who will understand?

Mam: Code means?
Yes, ma'am, dot dash or dash dot mam.
Cipher code or dot dash dash dash dot type—that is morse code.
Morse code, this is cipher code.
Ok, there are many types of coding. Just giving an example here. Ok, what I am saying is you are replacing the alphabet with another alphabet or letter for the alphabet.

Well, here are some examples. You have a separate field of study with encryption and decryption. You will be taught them in the fourth year. Well, what the cipher was saying is that I'm going to send you a sentence, and I'm replacing each letter of that sentence with another letter. What I'm going to do is, let me tell you what that is—I'm replacing "A" with "E." That means the letter gap between "A" and "E" is four. If you subtract four from the sentence you have, you will get the actual output. Then you will understand the meaning of my sentence. This is the cipher code. I am replacing one letter with another letter or with another digit.

The opposite of concealing information is revealing information, which is that the person I want to send the information to can see my code and understand what I mean. When you go to the super shop, you can't find many items; you can't find the price. Then, if you call a helper, he will help you by telling you the price. Now, you can't find it. He finds the item. Some codes are also given; by looking at the codes, you can tell that the price of this product is right. Now, you will not understand this code because he is concealing the information from you. He knows the meaning of the code. Look at an example here.

This is a code. If you see this code, you won't understand anything. For us, it is a few digits. But if you understand its inner meaning or can read this code, then you can easily tell from this code. What does it mean? For example, they say this code means "red maternity dress style 395 size ten." How do you understand? "202" means department. This department is the maternity department. "395" means what the style of the product will be. The style of each dress will be different. So "395" is representing that style. "40" is representing the color of that dress, and "10" is the size of the dress. Is that correct?

And "414219" means the seed winter coats department. "Color" is the seed. "219" is the style of the coat, and "12" is the size of the coat. Is that correct? So, those who are salesmen can decode this code very easily. Then another type of code—yes, that is mnemonic code. Mnemonic code is very easy. Mnemonic code is a short form of some big name, like Chittagong University of Engineering and Technology. Mnemonic code for something so big is "CHUTE." Ok, that's what you say. "CHUTE" is a mnemonic code. You are creating a code with the first letter of each word. "CHUTE" uniquely represents Chittagong University of Engineering and Technology.

Well, this is one type of code. Another is Unicode, which you all know is that the letters are not on our keyboard universally. What do we do with a few digits? With the help of some specific patterns, we can represent that digit. Ok, for that, there is that Unicode list. You use that Unicode. Using those codes, any or whatever is prescribed, you can type the corresponding letter of that code on the keyboard.

That is what is requesting.
Next: Appropriate Action.
Requesting Appropriate Action—what is it?
I am giving an example already. How can you request a task through code?

I told you yesterday that for your airport, you are going to select the airport from which you will take the flight. Then, you are going to select Dhaka Airport's code. You select the code, and they will select an action with respect to that code. What is the action? The action is that you will fly from Dhaka Airport.

Well, now see what is meant by function code. See the example: Code 1 means "Deliver," Code 2 means "Sold," Code 3 means "Lost," or "Stolen." What does it mean? Come on. It means you execute these functions through this code on the website you are using. If Code 1 comes to you, then it means your product is already delivered.

Now, your question may be: "Madam, how do I understand that delivery means that website or that organization?" That organization or that website will tell you: "1 means delivered, 2 means sold, 3 means spoil."

Okay, so these are function codes. Now, I am saying that the coding will be like this, so much like this. You can code one thing. What are the guidelines for coding? How do I code a product? There is no need to have a guideline.

There are eight types of guidelines. The first is concise size, which means short. So that the code doesn't become too long, like the Dhaka Airport code. I say "00." I couldn't make it longer if I wanted to, but now I've made it so long that it will take me more time to write the code or remember the code than it takes me to write "Hazrat Shahjalal International Airport."

Then my effective coding is not done. I want to code to shorten the big thing to remember it easily. So, whenever you create a code for something, you must remember that the code should be shorter than the original product or name, and it is easy to remember. OK, number two. The point is to keep the codes stable. It is very important to be stable. Do you think that today the code of Hazrat Shahjalal International Airport is 1? If the number 10 airport is created, then what will happen? Now, see, the above three and the above nine code digits are one each. The number 10 airport is its code digit 2.

The code that I am creating later in the future so that the code does not have to change much so that I can keep it to some extent stable. In one place, I code a product code. I give one letter with one digit. In another place, I give two digits. In another place, I give three digits. No, you will maintain stability. If you want to code your airport with one letter, then it must be one letter, and you can't use two letters to go to the place. Then there will be no stability, and that will not be effective coding. So you should think about the future.

Now, suppose there are 64 districts in Bangladesh. Even if you give one airport in each district, it is not more than two letters. In that case, you know that if I put a maximum of two letters for the name of the airport, then it is enough. In that case, do I understand? NCO's—that codes are unique—is also important. As I am sorting by code, in case of keeping track of which product, I can't give the same code for two different products, and in the future, so that my codes are not the same.

In that case, I am overlapping, but what will your system do? It will give wrong output. Now, is it not the fault of the system? You can't apply the code properly. It is your fault. Clear? Ok, then it is also important for codes to be sortable.

Now, suppose you are giving your date of birth somewhere. Now, by date of birth, I mean to serve the users that I have on my website according to their age. So, what you have to do now is pay your year; you have to pay the month, and you have to pay the date. Now, you have to pay the year in advance. If you give the day first or month first, your sorting will not be correct. If you give the year first, it will sort according to the year, which is more effective. When two years are the same, then it will sort according to the month. When two months are the same, then it will sort according to the day. So, when you take data input and set a code, you must keep it in mind so that the codes can be sorted and the codes can be classified.

OK, two number points: Always try to avoid it. It is

 normal, but it is good if you try to avoid it. For example, what can happen, like a letter and digit zero? If someone is reading on your website that you have given the name of the airport—have you given the name of Dhaka Airport? I told him, for example, and he understood that there are two letters in front of the alphabet. He thought it was two zeros. Now, he repeatedly clicks zero, and it is giving your input. Your system is not accepting input because zero is not the code; then, there is no code named zero here. Does the system take input, or does it take the alphabet "o"? Now, the user can actually confuse these things. Maybe you don't. Another human might.

Try to avoid the difference between zero and "o" that it can confuse people. You don't set the code like this.

Then it's: Keep the codes uniform. What I said earlier is that the codes must have stability and uniformity. What do I mean by uniformity? Hazrat Shahjalal is giving the airport code "HA." OK, "HA1" and Chittagong Airport code is "CHA." Suppose your first alphabet was Dhaka Airport 2 and Chittagong Airport alphabet is 3. So, is there no uniformity in it? Then keep these things in mind when you are coding for similar products. You will determine the code, then set the code so that there is uniformity between them. Try to set the code in a similar way.

Also, for modification of the code, it is very important. You have an airport today. Suppose five more will be created tomorrow. No? There is no guarantee. So, when you determine the codes for the current five airports, you have to keep in mind that my 64 districts may require up to 64 codes to be set. So, this modification space or adding something new to your code is OK. Make meaningful codes. This is also important. I did not say so much earlier that I will not understand anything by looking at a random number of digits, but the code has a specific meaning. Those who know this meaning can read the code very easily.

Now, you can enter a code with "1 2 3 4 5 6 7 8." If you make it, it doesn't really mean anything. In this way, it is not feasible to remember the different codes of each product. So, what you have to do is divide the codes into small parts first. OK, that's it. You see, we had five points of effective coding.

I read each point. What were the five points of effective coding? Why do I need coding? Now see if it matches. To do, to keep the information confidential from someone, to reveal it, and based on that code, I now understand what particular action to perform.

Hopefully, well, next is Effective and Efficient Data Capture. Now see, at the beginning of the class, we did not see the difference between effective and efficiency. Writing both together, effective and efficient data capture means data capture. What does it mean? To take data input effectively and efficiently. It means to take it accurately and to take it as fast as possible. I can understand. Now, what can we do for this? First, you need to decide what input you will take for your website, for your application.

OK, now suppose you are building an e-commerce website. Do you need a National Security Number on the e-commerce website, or do you need the ID card number of your National ID card? There's no need to be bulky or waste space, so you have to decide in advance that any information from the user is absolutely necessary for my work. The only things I'll do are take input from the user, and then let the computer do the rest. If you buy five items from a website, you are selecting five items and giving your required information. Now, take a look and see how the websites you buy from automatically add up the product prices of the five products plus what your shipping charges will be. The total does not show an amount.

So, who is doing these tasks? Actually, the system has done these tasks for you. Are you sitting and adding five prices to the system? The computer has done these tasks for you. What are you doing? You are selecting the products of your choice. The work is done by the computer; it does its work automatically. There is no need for you to intervene. I can explain that the work that the computer or the system can do by itself, you will give it to the user. Do not ask the user to calculate the price; the computer will do it automatically.

The number three point that will perform is the bottleneck and extra step. What is the bottleneck? Look at the different types of bottles. If you want to enter a lot of things at once, but it won't enter, then what will happen? It will be blocked. Also, your system is a small system. You are trying to enter thousands of information in that system at once. There is no chance of crashing your system. You have to avoid these things.

How to avoid: Do this as I said a little earlier; you do not give the user what the computer can do by itself. Do not take information from the user. There is no need to take extra information from the user because transactions mean work is a burden for your system. The less burden you give to your system, the more free your system will be. So, you will not give your system extra work. Then, the point is starting with a good form. Keep the form or registration form. You will take the necessary information in advance.

Ok, what will be the advantage of taking the necessary information in advance? The advantage is that you do not need to take that information from the user again and again. He will log in, and fetch all the information he has in his respect from the database. Again, there is no need to create a burden on the system by entering the information from the user.

Take data efficiently. You need a method to take data, so you have to collect the data in some way. The basic way is to type through the keyboard. The user will give the information by typing, or you can also give it through the Optical Character Recognition (OCR) machine. Scan that form and apply OCR to it, and it will automatically enter your inputs on your computer. Transfer can also be done. Also, there are other methods, such as MICR. Now, MICR is working everywhere, or giving examples of different places, that the data can be taken in this way. MICR—will you see in the bank now using MICR checks? MICR check—here is your information, encrypted through a code. When you give this MICR check, the information will automatically come to the computer. Those who are officers will scan the MICR check on their computer. What happens to him? He does not need to type the information extra.

Then comes the Marksense form, which we give in objective tests. You fill the circle to fill in the marksense given to you, then fill the circle, and sense the place that there is something here or block here. So, he marks you in different ways. You can input the data, but the common way is to use the keyboard while using a website. It is not so important.

Then, see: Ensuring data quality through input validation. How to keep my system free? Ok, now I have taken data input by following various techniques through code, by reducing the user's burden, saying that already save data without taking it from the user again. We have helped the user in various ways to take data input. Now, as much as you help the user, but the user will make mistakes. It's okay to make mistakes.

In that case, what will be your next measure? Your next measure will be input validation. You will validate the input that the user is giving.

OK, now let's see. Input validation also has a few points. One is validating input transactions, performing any action. First is submitting color data. If you have any color data, any color input, wrong input, then what will happen? According to that, the system will perform.

Assuming the Dhaka Airport code—you may forget to write the code of Chittagong Airport. In that case, your flight will be booked. Where is the transaction? From Chittagong Airport, but the transaction is also correct in terms of your input color data. Then, what can happen is the submission of data by an unauthorized person. The access will be there. The students are not supposed to get that access. Now, if a student gets my access somehow or the other, then it will not be his unauthorized access. He cannot change many things if he wants; it will not be right from my portal. No, this is my information as a teacher so that it does not go to a student. What should I do to keep it separate so that an unauthorized person cannot do any unauthorized work?

Then, asking the system to perform an unacceptable function. What do you think? I am 19th batch. In this role of CSC 133, an account named "1904133" is going to be opened for a student to input his file number. Then, will it not be an acceptable function because there is no roll named "133?" I can understand that there is not supposed to be a roll because there is no person here, so this kind of work—transaction or unacceptable action—these cannot be performed. The system must first validate that the input is valid, whether the input is authorized, and whether the input is acceptable. If they still go through these filters, I will see if my input is validated.

Now, input data can be validated. What kind of test for missing data can it be? Suppose you are filling out a form. OK, now during form filling, you have recorded fill.

 OK, you have not filled all the recorded fields to give your phone number in one place. It was said that if you don't give your phone number or unintentionally, then if he accepts that form, what will happen? It is information missing, which is not desirable in any way, so you have to validate all the information he has given. If not, then you have to take that data from him again.

The next test is for the correct field. Now, you are taking the National ID card number during form filling, and it is important. In that case, our National ID card is supposed to be ten digits. Ten digits. Now, instead of ten digits, if someone gives nine digits or eleven digits by mistake, less or more, then it is not valid. It is not your National Security Number. It should be checked from the perspective of Bangladesh that he has given the correct National ID card.

Then, there is a test for class or composition. It is assumed that your National ID card number is all digits, and there are no letters. His National ID card number is zero, but he is pressing on the keyboard. And what will happen is that it will be wrong. Then immediately, what you can do is call it wrong because you know there will be no letter in the National ID card number. He is pressing a letter, and you are validating the composition of that field by doing a test.

Then, it is a test for range or reasonableness. What will be the reasonableness? That is the example I gave a little earlier. Page 19 has rolls up to 132. When I go to input the number 133, it will say that it is unreasonable or it is out of range because 132. No one can be outside. Ok, then a test for invalid values. Invalid values—what do you think? You have given the function code. If you register 1 and if 2, then not register. Now, if you give value 3, which in your system no code is set in any case for 3, then the system will not take it. It will show a cross and say that you input a valid code, 1 or 2 reasons. Otherwise, it will not be registered.

Then there is a cross-reference check. Your system will check and see that your address is saying that you are in a chat, or a chat but it doesn't fall in. Then in Raozan, it will tell you that the chat you are writing is not matching with the chat. Fix it. Validity checked. This is called a cross-reference check. Check if one input is compatible with another input you validate.

Now, see. Well, there are a few more points: Test for comparison with stored data. Is this very easy? This is password checking. You set a password for your profile. Every time you go to log in to that website, you will compare the given password with the previous stored password and see if your password is correct.

Validating codes, check codes. Ok, now check digit—what is it? You do it with a code generated from that code. Add a digit to that code. OK, how do you add it? Why do you add it? Coming—what did you do? A code is given to you. From that code, you generate a digit and add that digit to that particular code. Ok, now, after adding the code, what will be at the receiver's end or the system at the receiver's end? The system is giving input. You are the sender, and you are the receiver. If your last digit matches the code you input, then you can input the correct code. If it doesn't match, then you cannot input the correct code. I can't explain how to do it.

With these few points, you have seen how you can validate your input or user input into the system.

Well, our topic was that we will validate the inputs we give and ensure data quality because if wrong stuff is input, my data quality can't be ensured. It is checking whether the input he is giving is valid. Now, let's come to the check digit of the last point. How can I generate it? First, see the procedure. Then, if you have any questions, do you have a particular number, any product number?

Suppose any product. You want to order a shirt. The product code of that shirt is 54823. Now, what you have to do is input 548. Now, what your system will do is generate a check digit from 54823. How? First, it will select a weighing method and select a modulus number. This weighing method will be used by the system analyst or developer according to their wishes. OK, here it is being used. 1 3 1 3 1 3. What happens if 5 is multiplied by 1, 4 is multiplied by 3, 8 is multiplied by 1, 2 is multiplied by 3, and 3 is multiplied by 1? Then I will add the multiplied values. The value will be 34. I will divide this 34 by the modulus number that I am selecting. After getting a value of 6, what do you do with this 6? Add it to the code I had. Then, my generated code is 548236.

Ok, everyone agrees? Ok, now how is the work done? The actual code of your shirt is 54823, and the check digit is 6. The code of your shirt product is 548236. Ok. Now, if for some reason you make a mistake in this code, like three instead of two or five instead of eight, in that case, will your check digit be generated? Or, even if it is generated, will it be 6? 54833—what is the check digit for this code? Hurry up. You must generate the check digit according to this rule. You have to generate the check digit by following the same rule. The generation of check digit at the sender and receiver's ends should be the same. Code is 5483—what is the check digit for this code? It is found out—3 will be 3. How much, sir? 3? 3. Then see, your check digit is changing due to a change of only one digit.

So, when you are going to order a product, the system will then generate the check digit from that code and see if the last digit of the code you input and the check digit it is generating are equal. If you input it, and if not, then it will say that you have not input the correct code. There is a mistake in the code.

You can catch modulus 10, you can catch modulus 9, no problem. Then 2 1 2 is your weighing method. It can be the arithmetic method. What kind of arithmetic method? It can catch 2 3 4 5 6 from the right-hand side like this, or 3 4 5 6 7 from the right-hand side. No problem. Arithmetic means increasing one by one. The geometric method can be what happens to all multiply by power of 2. These are different ways you can generate check digits. No problem. Now, how will it come in the exam? Actually, I will give you a weighing method and a modulus number. What will you do from there? Generate the check digit using the clear generation technique. But what will happen to the previous one? You will subtract the remaining remainder from the modulus number, and the remaining value will be your check digit.

Clear? Well, there is another Lun formula. The Lun formula is a little different from it. Weighing method. If the modulus number is given, then follow this technique very clearly. Break it down. I told you that if you make a mistake, the number will be cut.

Clear? OK, now let's see what the Lun formula says. See, the Lun formula is a check digit generation technique. Just the technique is different. What to do? What to do with the second last digit? Multiply it, double it. You see the number 778 is given to you. Multiply it by 1 minus 1, so what happens? Drop the last digit, drop 8, drop 8, and double the next digit. Double 16, then drop the last digit. Go to 8, then double 7, then double 14, then subtract 7, then double will be 14. So what is my total? 14, 7, 14, 8, 16, 8—this is my total number. Now, among these numbers which are in double digits, how do I add them to single digits? What is a double digit? 14, then add 14—1 and 4, 5, then 7—it is a single digit—then 14, 5, then 8, then 1 and 6—7, then 8.

Then, now, what is my number? 5 7 5 7 8. Ok, next, you add all the numbers, and you get 5 + 7 + 5 + 8 + 7 + 40. Now, look. Total number is Validating Formula. Lun Formula. Test Lun Formula. Only for checking the credit card number of a particular country. It is used for that country. So, they are following this technique because they set the codes for credit card numbers in that way. It is not a universal technique, but it has a name: Lun Formula. The number is valid, and if there is anything other than zero, then it can be said that the credit card number is fake. It is universal. Any credit card number, if you check this way, you will get the perfect result. No, it is for any country. They are designing their credit

 cards like that.

Generate and clear the credit card numbers. Well, then we come to the accuracy advantages in e-commerce environments. Actually, you don't see anything like that. When we buy and sell on e-commerce websites, you—the user—give your information on the website. So, we can say from the user. Directly, the data we are inputting in the system has very little chance of error. Then, the data entered by customers and stored for later use—as the e-commerce website is a completely online-based system—then I have to maintain a database to store the information you give on the website. In the database, I can later use that information for my point of sale and fulfillment process.

For example, suppose you buy a product from a website today with a particular address, or a chat address. If you want to buy another product from the same website, what should he do? He can fill the address field by default. Don't fix it at all; if he wants to take the order from another place, you will also give him the option to remove it. Time buys the product for us, so if you set the default address, the user doesn't have to type it again. You're giving him an advantage, and he'll be happy. You can use these as feedback from the customer. These are the advantages of using this e-commerce website. I can very well ensure user satisfaction through this e-commerce website.

If anyone has any questions, that's it.
Sir: That's all for today.
There will be another class tomorrow from seven o'clock.
There is another chapter.
Then, the end is fine.
Thank you, sir.
Mam: See me, today's attendance means today's class. Like yesterday's class, please give us a little.
Ok, ma'am.
Mam: It's ok.
Yes, ma'am.
Sir: Assalamu Alaikum.