|
Apologies Luc, bear with me please I will get there eventually.
|
|
|
|
|
|
I am re-posting this because for some odd reason I posted first time in the wrong place, if this is wrong also I am not sure what I will do but here goes.
I agree that the problem should be split into small pieces and that verifying the serial side of things would be a good place to begin.
Can we see the instructions from the arduino that actually transmit the data, the fact you are using a micro controller gives you a certain degree of control over the serial protocol.
I assume the data is being transmitted in a loop, how fast is the controller repeating the transmission loop and at what baud rate.
If the transmission is too fast then it might not be possible to process the incoming and update a chart at the same time without buffer over run, which would be pointless anyway because you would be unable to read the chart as it updated at those speeds, this can be overcome by storing the data in memory and displaying it at a slower rate but this also has its limitations.
|
|
|
|
|
One more question...
In C# you have
'animal fox = new animal()'
Why do you need to repeat the word animal? Why not have 'fox = new animal()'
Brian
|
|
|
|
|
So that C# "knows" what kind of objects can be put in it!
Remember that a variable can contain an instance of the type it was declared as, plus any derived types.
So is you have a class hierarchy:
class Animal {}
class Mammal : Animal {}
class Birds : Animal {}
class Fish : Animal {}
class Reptiles : Animal {}
class Amphibian : Animal {}
class Fox : Mammal {} Then declaring createurs is legal:
Fox fox = new Fox(); And
Mammal mammal = new Fox(); And so is this:
Bird eagle = new Eagle(); And you can do this:
Animal animal = fox;
animal = eagle;
animal = mammal; But you can't do this:
eagle = fox; Or this:
eagle = mammal; Or even:
fox = eagle; Because they don't make any sense in a real world.
Telling C# what type of object a variable can contain means it can catch errors at compile time instead of when your program is running, which makes your code both easier to read and more reliable.
Sent from my Amstrad PC 1640
Never throw anything away, Griff
Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...
AntiTwitter: @DalekDave is now a follower!
|
|
|
|
|
Thanks Griff for the examples
If you have this code:
class Bird : Animal {}
Bird eagle = new Eagle();
then saying
animal = eagle;
is like saying
animal = animal
as they both should have the same properties.
Please correct me if I'm wrong
I see what you mean by real world. A bit like saying circle = square
Brian
|
|
|
|
|
public class Animal
{
public void Breathe() {}
}
public class Bird : Animal
{
public void FlapWings() {}
}
public class Eagle : Bird
{
public void DiveVeryQuicklyOntoOtherBird(Bird target) {}
}
...
Bird eagle = new Eagle();
Animal animal = eagle; That's completely legal because Eagle is derived from Bird, which derives from Animal: an Eagle is a Bird, which is an Animal.
But ... it's legal to say these:
eagle.FlapWings();
eagle.Breathe(); Because eagle is a variable containing a Bird instance (or an instance of a class derived from Bird ), so it has all the properties and methods of a Bird as well as those of an Animal
But ... you can't do this:
eagle.DiveVeryQuicklyOntoOtherBird(myPigeon); Because not all the types that can be held in a Bird variable are Eagle s; they could be any Bird - so they don't all support the DiveVeryQuicklyOntoOtherBird method - despite the variable currently containing an instance of an Eagle the system doesn't "know" that it always will; at a later point you could replace it with
eagle = new Sparrow(); which can't dive really quickly like an apex predator!
To use the method you'd need to cast the instance:
((Eagle)eagle).DiveVeryQuicklyOntoOtherBird(new Sparrow());
Or use an Eagle variable.
If you try to cast a Sparrow to an Eagle, you will get an error at run time, because that's the only time when it can check if the conversion is possible.
Sent from my Amstrad PC 1640
Never throw anything away, Griff
Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...
AntiTwitter: @DalekDave is now a follower!
|
|
|
|
|
Thanks Griff.
I liked examples like these you've given me.
You wrote::
eagle = new Sparrow()
I thought you may have to use:
Bird eagle = new Sparrow()
.
Is it because you have already defined the eagle as a bird (Bird eagle = new Eagle();) that you don't need to do this?
Brian
|
|
|
|
|
If you do this:
private void DoSummat()
{
Bird eagle = new Eagle();
...
eagle = new Sparrow();
...
} You are just reusing the existing variable, like you do without worrying about classes:
int i = 1;
while (true)
{
Console.WriteLine(i);
i = i + 1;
} If you tried to create a new variable with the same name in the same scope:
private void DoSummat()
{
Bird eagle = new Eagle();
...
Bird eagle = new Sparrow();
...
} You would get an error as it already exists - just the same as you can't do this:
for (int i = 0; i < 10; i++)
{
Console.Write($"{i} :");
for (int i = 100; i < 110; i++)
{
Console.Write(i);
}
Console.WriteLine();
} You can't have two loop guards with the same name!
Or even this:
private void DoSummat(int x)
{
int x = 666;
...
} Because the parameter and variable are the same name.
Sent from my Amstrad PC 1640
Never throw anything away, Griff
Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...
AntiTwitter: @DalekDave is now a follower!
|
|
|
|
|
Now I've had some coffee, I'll add some thoughts for you.
If you allowed
fox = new animal(); without the type specifier, what problems might it cause?
Well, consider this:
public animal fox { get; set; }
public void DoSummat(animal a)
{
fox = a;
...
} Is the fox assignment inside DoSummat meant to create a new local instance which is scoped to just the method, or to affect the public property? How could you tell? How could I tell when I tried to fix a problem in 100,000 lines of code next year?
Worse, is fox supposed to be an animal , or a mammal , or a Canidae ? Does it make a difference? Yes - it does. Because bird is a type of animal but a fox doesn't have a FlapWings method! So if you allow implicit typing, then the compiler has to assume the lowest common type in the hierarchy and that could mean that methods you expect to work just don't exist for that actual instance.
And consider this:
public void DoSummat(animal a)
{
fox = a;
...
fax = b;
...
} Isfax a new variable, or did I mistype fox ? How would you tell?
C# is a strongly typed language: which means that there is no implicit declarations, no automatic type changing (except where data won't be lost such as int to double for example), and heavy duty type checking - which makes your code more robust because it finds problems at compile time, instead of hoping you tested all the possible routes through the code and didn't leave a "bad type" in there.
Sent from my Amstrad PC 1640
Never throw anything away, Griff
Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...
AntiTwitter: @DalekDave is now a follower!
|
|
|
|
|
I do like the way you need to define all variables in C# unlike Python where you could start by attaching a string to a variable then later in the code attach a number to the same variable. Python accepts this without giving any errors
It can cause lots of problems in getting a program to work correctly.
Speaking of languages I wonder what happened to Visual Basic which was once a popular language. It's no longer in the top 10 popular languages.
I suspect C# would be popular with people who have learnt C and C++ as it's simlar in some ways to those languages.
I decided to learn C# as I wanted a language to create programs in Windows (that were exe) that had a console and would run fast. Also I prefer compiled code to scripting code.
Brian
|
|
|
|
|
Some good caffeine in there !
«Where is the Life we have lost in living? Where is the wisdom we have lost in knowledge? Where is the knowledge we have lost in information?» T. S. Elliot
|
|
|
|
|
Heavy duty wake up juice!
Sent from my Amstrad PC 1640
Never throw anything away, Griff
Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...
AntiTwitter: @DalekDave is now a follower!
|
|
|
|
|
OriginalGriff wrote: without the type specifier, what problems might it cause?
Hmmm...I can see the compiler struggling a bit with the following....
var fox = new;
|
|
|
|
|
For local variables, it's not necessary to repeat the type name:
var - C# Reference | Microsoft Docs[^]
Implicitly typed local variables - C# Programming Guide | Microsoft Docs[^]
The following two lines produce identical IL:
Animal fox = new Animal();
var fox = new Animal();
NB: You can't use var for fields, property types, method parameters, or return types.
Why no var on fields? – Fabulous Adventures In Coding[^]
There is a suggestion which would allow fields declared as: Animal fox = new(); , but it hasn't been implemented yet:
csharplang/target-typed-new.md at master · dotnet/csharplang · GitHub[^]
NB2: Some people vehemently oppose any use of var beyond anonymous types. And it certainly can be overused - for example, var x = Foo(); would compile, but is not readable. But for a new expression, where the type is right next to the variable declaration, I don't see any problem with using var .
NB3: To clarify, based on the responses: using var for new expressions is fine; you should generally avoid it for anything else.
var x = new SomeType(); is fine.var x = SomeMethod(); is bad.
"These people looked deep within my soul and assigned me a number based on the order in which I joined."
- Homer
modified 16-May-19 9:45am.
|
|
|
|
|
Personally, I'd recommend that beginners avoid var until they get to Linq, just to make it more obvious to them exactly what they are doing.
But at least it's less horrendous than misused dynamic ...
Sent from my Amstrad PC 1640
Never throw anything away, Griff
Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...
AntiTwitter: @DalekDave is now a follower!
|
|
|
|
|
Use "var" to help "keep you coding" if you're not sure what type is returned. (Methods; LINQ).
THEN, after intelli-sense has resolved the type, you can then "mouse over the var" and convert it to an explicit type ("quick action" refactor).
Perfect for a student (and memory-poor me), IMO.
"(I) am amazed to see myself here rather than there ... now rather than then".
― Blaise Pascal
|
|
|
|
|
Until you get to Linq, you should have a good idea what type you are using - particularly when you are just starting. I think explicit typing helps beginners rather than confuses them when they suddenly find it "won't pass x to method y" and can't understand why not.
But hey! I'm not going to start a flame war about it!
Sent from my Amstrad PC 1640
Never throw anything away, Griff
Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...
AntiTwitter: @DalekDave is now a follower!
|
|
|
|
|
OriginalGriff wrote: I'm not going to start a flame war Oh come on, we need a bit of excitement sometimes.
|
|
|
|
|
Reminds of "History" classes ... memorizing dates before they meant something.
Different strokes.
"(I) am amazed to see myself here rather than there ... now rather than then".
― Blaise Pascal
|
|
|
|
|
Yes Gerry I've found intelli-sense very useful. Great tool tool for beginners.
Brian
|
|
|
|
|
I agree with OriginalGriff. Telling newbies to use var probably means that they will never use proper types.
|
|
|
|
|
Which is why I added the note that it's best saved for new expressions.
Bad: var x = Foo();
Good: var x = new Bar();
"These people looked deep within my soul and assigned me a number based on the order in which I joined."
- Homer
|
|
|
|
|
Richard Deeming wrote: Which is why ... In the forlorn hope that your advice will be properly listened to.
|
|
|
|
|
There's a first time for everything.
"These people looked deep within my soul and assigned me a number based on the order in which I joined."
- Homer
|
|
|
|