C# math question.

[bob7122]

I have an exam this week and the math concept specifically ROUNDING is being brought up by my classmates and I need some clarification.

I am stating that if both operands are integers then my answer will be in integer form, BUT YOU ROUND DOWN ALWAYS.

What would the answer be for a math problem like the following? we don't need decimals its just integers EXAMPLE: X = 5/2=2.5 but the integer is rounded down to the final answer of 2, NOT 3.


problem being debated is :

7/2=3.5 but written in integer form wouldn't it be 3 and not 4?

I thought the computer would automatically round down? Am I off?

we are not using double data type or decimal.round method. I read that there is something like the banking method where you round to the closest even number and another method where you round to the number furthest away from zero. BUT we did not cover any of that in class.

[Woodythedog]

The answer is ....buy both.

[Pandanin]

It doesn't round; instead it drops the decimal portion of the number.

So yes, 5/2 = 2.5

(int)2.5 = 2

[bob7122]

It doesn't round; instead it drops the decimal portion of the number.

So yes, 5/2 = 2.5

(int)2.5 = 2

thank you.

would it apply to 7/2 = 3?

[Pandanin]

thank you.

would it apply to 7/2 = 3?

Yes.

The left side of the decimal is the 'whole number' and the right side is the 'decimal'.

For programming languages, the INT function returns the whole number and drops the 'decimal' completely.

(int)5.999999999 = 5
(int)5.111111111 = 5

[bob7122]

Yes.

The left side of the decimal is the 'whole number' and the right side is the 'decimal'.

For programming languages, the INT function returns the whole number and drops the 'decimal' completely.

(int)5.999999999 = 5
(int)5.111111111 = 5

thank you so much!

[Robotron2k84]

Yes, division returns integers unless overloaded by casting the return value as a floating point or precision type. In this case it's up to the language to integrate the remainder and the simple division product.

However, if you want the remainder, only, use the mod() function of your language.

X = 7/2 [X will be 3]
X = 7%2 [X will be 0.5]

If X is cast as an int in the second case, the result is 0.

Modulo functionally is one of the most basic compiler optimizations across platforms. Some chips operate on bitwise transforms faster than remainder calculations, and a compiler makes that choice to speed up program execution.

https://en.wikipedia.org/wiki/Modulo_operation

[sealocan]

5/7 ?

[Deedle]

I have an exam this week and the math concept specifically ROUNDING is being brought up by my classmates and I need some clarification.

I am stating that if both operands are integers then my answer will be in integer form, BUT YOU ROUND DOWN ALWAYS.

Conversion of a floating point type to integer type will truncate, which means it will always 'round toward zero', so for negative numbers it actually rounds up if you see what I mean.

Not sure about C#, but I assume it's the same as they tended to keep things the same as a C guy would expect. C has a function called floor() that always rounds down, maybe C# has this as well.

[kemasa]

It isn't rounding, it is truncation. Integers have no fractions.

[Fastattack]

HELP is your friend.

https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/operators/division-operator

[bob7122]

Yes, division returns integers unless overloaded by casting the return value as a floating point or precision type. In this case it's up to the language to integrate the remainder and the simple division product.

However, if you want the remainder, only, use the mod() function of your language.

X = 7/2 [X will be 3]
X = 7%2 [X will be 0.5]

If X is cast as an int in the second case, the result is 0.

Modulo functionally is one of the most basic compiler optimizations across platforms. Some chips operate on bitwise transforms faster than remainder calculations, and a compiler makes that choice to speed up program execution.

https://en.wikipedia.org/wiki/Modulo_operation

5/7 ?

Conversion of a floating point type to integer type will truncate, which means it will always 'round toward zero', so for negative numbers it actually rounds up if you see what I mean.

Not sure about C#, but I assume it's the same as they tended to keep things the same as a C guy would expect. C has a function called floor() that always rounds down, maybe C# has this as well.

It isn't rounding, it is truncation. Integers have no fractions.

HELP is your friend.
https://docs.microsoft.com/en-us/dot...ision-operator

Thank you all so much!

[AN40]

Damn man, when you read the text and actually do the examples in a compiler. It helps build logical intuition. Most important skill for a programmer is logic.

Also, learn how to google. All the resources are out there. A non-resourceful programmer is an unemployed programmer.

[Robotron2k84]

One thing:

I realized I made a mistake in my explanation of the mod function. Mod returns whole numbers as the difference of the dividend and the product multipled by the denominator.

You actually have to perform mod / denominator as a float to get the decimal representation of the fractional product.

Updated example:

X = (7%2)/2.0 [X will be 0.5, dividing by 2.0 casts return as float]

Sorry for the confusion.

[BigFatGuy]

If you don't mind a bit of free advice from someone who flunked out of school, then became an honors student, a teacher, and is now writing (vhdl) code for a satellite project I can't talk about in public:

if you wonder "what will happen with this code", write the code and run it to find out.

"Why does this strange thing happen" is a much better question than "what will happen". Your job, basically, for the rest of your career, is to impress your (teachers/bosses/coworkers/lovers) with how hard working, curious, and resourceful you are.