05 - Operators and Operations with primitive types/002 Operations with integers and floating-point numbers, BigDecimal type_en.srt

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Yes, students in this lesson, I would like to draw attention to some operations with integers and

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floating point numbers.

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Let's start with use this example.

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Imagine you want to divide two integers.

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Let's imagine you're implementing overapplication and you want to split the right charge between you

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and your friends.

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If right charge was 20 bucks and there were three of you, each of you should pay for six bucks.

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According to the results of our program, probably each of you will be happy because you all together

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saved two bucks, but Uber driver will hit you up.

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You need to remember that when you are dividing integers, you receive integer and there is no rounding

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fractional.

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Part of the result is just not taken into account what you can do about it now.

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Just change type of the option to double to get floating point number as a result.

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You see, I am custom integer to double here and right in the program, we'll run with you more about

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expression, type in the separate less than.

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Now you see double the result, but still this is something what the end user wouldn't expect and can't

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pay exactly this amount of money.

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So what to do in this case?

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The rule of thumb here is to use big decimal object.

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In previous lessons, we learned how to attach source code to eclipse and how to investigate the source

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code.

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So feel free to open Javadoc for that small type.

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To learn more.

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The big Desmonte class provides reparations for arithmetic, scale manipulation around in.

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Also, this class gives its user complete control of around in behavior, if no round in mode is specified

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and the exact result cannot be represented, an exception is thrown.

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Let's declare a variable of big decimal type here.

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To create object, object that small use, special method value of like this and calling value of method

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here of big decimal type.

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This message represents gradational architecture, Partan, which is called factory method.

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We'll discuss portions in the separate lesson for now.

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Just remember how to create an object of that small type.

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You can also set scale for this number.

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We are having to deal with money here.

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So let me set a scale of two.

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This is our right feet.

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Let's create a new variable which will contain amount of people.

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We have three people.

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And now let's divide right feet by amount of people without rounding more specified, we'll have arithmetic

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exception like this.

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Our program wants to tell us that we can't show the exact calculation result.

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Let's set up around in put call my hair in mode.

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Not.

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You can choose out of different rounded modes here, but let's select the one we learned at school.

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And now let's bring the result to console.

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And runs the program.

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And now we see the results, which we were expected to see.

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Let's also review operations with double imagine you have some double number three point one, and you

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need to subtract from it one point twenty one when you subtract double value from double value.

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You will see a result like this.

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The funny story that I order a pizza online recently and applied my bonuses as a result, I got no like

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this.

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I asked them how they would like me to pay this amount of money we love to meet.

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But still, as a programmer, you need to know what to do.

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In such cases.

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There are infinite number of real numbers in any range, but only a finite number of bits to represent

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them.

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For this reason, a rounding error is expected for doubles and flaws.

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The number you get is the closest number possible that can be represented by double in 14 points representation.

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Here's where Big Decimal was rounding.

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What will help us?

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Let's create the objects of big decimal here, do not forget to set the scale for them.

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And let's subtract this number from this one, I'm right in the program and here is the result.

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Today, you learned how to control precision in arithmetic operations and how to set up around in the

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rules.