(Sum the digits in an integer) Write a program that reads an...

Key Concepts

Arithmetic Operations

Basic arithmetic operations, specifically addition, are used to accumulate the sum of the extracted digits as they are processed iteratively. This fundamental operation ties the extraction process together by providing a mechanism to compute the final result.

Modulo Operator

The modulo operator is used in programming to extract the remainder of a division between two numbers. It is crucial for digit extraction because performing a modulo operation by 10 on an integer yields its last digit, which is a key step in breaking down a number into its individual digits.

Integer Division

Integer division is used to reduce the number by removing its extracted digit. Dividing an integer by 10, for instance, shifts the digits to the right, effectively discarding the last digit that has just been processed. This operation is essential for iteratively processing each digit of the number.

Iterative Processing (Looping Constructs)

Looping constructs such as 'while' or 'for' loops are employed to repeatedly apply the digit extraction and removal techniques until the number is reduced to zero. This allows the systematic accumulation of the sum of all the digits in the number.

Transcript

00:01 In this video, we will write a program that reads an integer between 0 and 1 ,000 and adds all the digits in the integer.

00:07 For example, if our number was 932, the sum of the digits would be 14.

00:14 We can use the modulist operator to extract the 1s digit.

00:20 We can also use the integer division operator to remove the 1s digit.

00:27 If we're using these both the 10, so mod 10 would get us the one digit and integer divide by 10 would truncate the one digit.

00:40 So we can go ahead and import java .util .scanner, since we know we'll be taking user input.

00:59 Next, we can go into our main method and we can create a new scanner object, call it.

01:05 Input and we can use system .in a predefined object as an argument because this represents the standard input stream.

01:20 The next thing we're going to want to do is to prompt the user to enter a number between 0 and 1000.

01:32 To do this, we can use system .out .print .l .n.

01:51 The next thing we're going to want to do is store.

01:54 This and we can call it number equals input.

01:59 Nextinth, which is a method of the scanner class that ensures our input is being stored as an integer.

02:23 Next, we're going to want to create another integer.

02:27 We'll call it n and we can set this to number.

02:30 We're going to create another integer n since we'll be creating a while loop.

02:36 Now you could, because the question is, asks for an integer between 0 and 1 ,000, you could take any number and calculate the ones, tens, and hundreds digits, and then sum those.

02:51 But i think for practice, it's better to use a while loop because this would be applicable to any number, any bigger number, and it kind of explains what's happening along the way.

03:03 So we can do int sum because in our while loop, we're going to want to calculate the sum.

03:09 We'll need some starting to start.

03:10 At zero so we can add to this.

03:12 We'll create our while loop and our condition will be when n is greater than zero because every time we enter the while loop we're going to end up removing a digit so eventually our n will go to zero.

03:30 Now it's important that we don't use number in case we want to use the number at the end of the program maybe we want it for something else.

03:41 It's important to realize which numbers you're going to be editing within a loop, et cetera.

03:50 So i suppose our input is 932.

03:55 932 is greater than zero.

03:57 So we're going to enter the y loop, and we're going to want to take off the one's digit two.

04:04 So we can do that by doing n mod 10, but we're going to want to add it to some, so we can do that by doing sum plus equals n mod 10.

04:12 And this is the same as sum equals sum plus n on 10...

Please give Ace some feedback