1. Requesting help again... as a beginner....
- Posted by Mattymatt May 23, 2009
- 978 views
Okay, I got started writing a math program, and I wanted to know is there a way to make the statement 'if' do something only if it gets an odd number. For example...
atom a a = gets(KEYBOARD) if a = ODDNUMBER then ... puts(1,"\nThat is an odd number.") end if
How do I make it so that if a person types in an odd number, then that message would come up? What do I put in place of 'ODDNUMBER'? Sorry, I couldn't think of an easier way to say that question, but I hope you understand what I am asking.... Also, would all of that be right in syntax? I put it in .exw, if that matters, and I am using Euphoria 3.1.1. And.... what is \n used for? I am basing this off of the source code of the demo Animal. I did read what /n does in ABGTE, but I didn't understand. It said something like:
Data has outputted in text mode has carriage return codes (13 or ‘\r’) added before any line feed codes (10 or ‘/n’)
Can someone explain it to me a little bit better? Or is that the simplest form it can be explained in? Thanks for the help!
2. Re: Requesting help again... as a beginner....
- Posted by jimcbrown (admin) May 23, 2009
- 966 views
Okay, I got started writing a math program, and I wanted to know is there a way to make the statement 'if' do something only if it gets an odd number. For example...
atom a a = gets(KEYBOARD) if a = ODDNUMBER then ... puts(1,"\nThat is an odd number.") end if
How do I make it so that if a person types in an odd number, then that message would come up? What do I put in place of 'ODDNUMBER'?
You can't. Nothing will fit. However, you can do this:
if remainder(a, 2) != 0 then puts(1,"\nThat is an odd number.") end if
Since by definition, odd numbers are not divisible by two, and so they will have a remainder.
You have another problem, basically gets(KEYBOARD) does not return a number but it returns a sequence. It returns a string of what the user typed, which can not be used as a number directly.
You probably want to use prompt_number() in get.e instead.
Sorry, I couldn't think of an easier way to say that question, but I hope you understand what I am asking.... Also, would all of that be right in syntax? I put it in .exw, if that matters, and I am using Euphoria 3.1.1. And.... what is \n used for? I am basing this off of the source code of the demo Animal. I did read what /n does in ABGTE, but I didn't understand. It said something like:
Data has outputted in text mode has carriage return codes (13 or ‘\r’) added before any line feed codes (10 or ‘/n’)
Can someone explain it to me a little bit better? Or is that the simplest form it can be explained in? Thanks for the help!
It is always \n and \r, never use /n or /r.
The \ is a backslash, and the / is a forward slash.
Basically, \n is a new line. So if you have a string like "Hello.\nThis is some text.", when you print that string it will show up like this:
Hello. This is some text.
But if you put it into a file, it is turned into "Hello.\r\nThis is some text." as this is the DOS text file format. The DOS text file format is a discussion in and of itself.
Btw, if you did a puts(1, "\r") then that would move the cursor back to the first column but it would stay on the same row, the same line. This might be useful if you wanted to erase a line or overwrite a line with new text.
3. Re: Requesting help again... as a beginner....
- Posted by jiri May 23, 2009
- 978 views
- Last edited May 24, 2009
if remainder(a, 2) != 0 then puts(1,"\nThat is an odd number.") end if
Bits twiddling is neater and faster:
if and_bits(a, 1) then ...
jiri
4. Re: Requesting help again... as a beginner....
- Posted by DerekParnell (admin) May 24, 2009
- 967 views
if remainder(a, 2) != 0 then puts(1,"\nThat is an odd number.") end if
Bits twiddling is neater and faster:
if and_bits(a, 1) then ...
jiri
Yes, but needs more explanation for a newcomer.
The remainder() idea just works on the premise that odd numbers always have a remainder of 1 when divided by 2. However, dividing is often slower than most other arithmetic operations.
The bit twiddling idea works by knowing that the way that computers store numbers in memory. All numbers are just a set of bits (ones and zeros). In Euphoria, whole numbers use a set of 31-bits and the number of combinations that these have means that it can easily store all the whole numbers from -1,073,741,824 to +1,073,741,823. However, every odd number always has the 31st bit set to 1 and even numbers always have this set to 0. The and_bits() function does a binary 'and' operation on every bit in the two sets of bits supplied in its parameters. An 'and' operation simply returns 0 if either bit is a zero, and returns a 1 if both bits are 1.
So testing for oddness using and_bits(a, 1) is just this ...
31-bits in 'a' = xxx xxxx xxxx xxxx xxxx xxxx xxxx xxxx xxxx 31-bits in 1 = 000 0000 0000 0000 0000 0000 0000 0000 0001Where the 'x' is either 1 or 0. Because all but the 31st bit in '1' is zero, the results for anding these are also zero. But with that last bit, if 'a' is odd then its last bit is 1 otherwise 0 (even). So odd numbers 'and' 1 and 1 ==> 1, and even numbers 'and' 0 and 1 ==> 0.
Therefore, and_bits(a,1) for odd numbers always returns 1 and 0 for even numbers, and this is a lot faster than doing a division.
As this comes up frequently, I'll add it as a standard function to the math.e library for v4. The inlining feature should ensure that this will not have a function call overhead.
5. Re: Requesting help again... as a beginner....
- Posted by Mattymatt May 24, 2009
- 1006 views
if remainder(a, 2) != 0 then puts(1,"\nThat is an odd number.") end if
Bits twiddling is neater and faster:
if and_bits(a, 1) then ...
jiri
Yes, but needs more explanation for a newcomer.
The remainder() idea just works on the premise that odd numbers always have a remainder of 1 when divided by 2. However, dividing is often slower than most other arithmetic operations.
The bit twiddling idea works by knowing that the way that computers store numbers in memory. All numbers are just a set of bits (ones and zeros). In Euphoria, whole numbers use a set of 31-bits and the number of combinations that these have means that it can easily store all the whole numbers from -1,073,741,824 to +1,073,741,823. However, every odd number always has the 31st bit set to 1 and even numbers always have this set to 0. The and_bits() function does a binary 'and' operation on every bit in the two sets of bits supplied in its parameters. An 'and' operation simply returns 0 if either bit is a zero, and returns a 1 if both bits are 1.
So testing for oddness using and_bits(a, 1) is just this ...
31-bits in 'a' = xxx xxxx xxxx xxxx xxxx xxxx xxxx xxxx xxxx 31-bits in 1 = 000 0000 0000 0000 0000 0000 0000 0000 0001Where the 'x' is either 1 or 0. Because all but the 31st bit in '1' is zero, the results for anding these are also zero. But with that last bit, if 'a' is odd then its last bit is 1 otherwise 0 (even). So odd numbers 'and' 1 and 1 ==> 1, and even numbers 'and' 0 and 1 ==> 0.
Therefore, and_bits(a,1) for odd numbers always returns 1 and 0 for even numbers, and this is a lot faster than doing a division.
As this comes up frequently, I'll add it as a standard function to the math.e library for v4. The inlining feature should ensure that this will not have a function call overhead.
Alright, thanks. Is there a way to copy the code out of the editor, so I don't have to retype it? Anyways, heres what I got so far, but I have this ex.err that keeps saying I should have end instead. Heres just the segment of it that it reads up to.
sequence t integer h, e t = {1,10000} while t = {1,10000} do t = prompt_number("\nPlease enter a positive odd number.") if t <= 2 then puts(1,"\nThat is an unusable number.") t = {1,10000} else t = and_bits(t,1) power(t,2) = h ____________________ puts(1,h)
(I didn't know how to indent in eucode) The ex.err shows <eucode> power(t,2) = h</eucode>
^ is under r at power.
expected to see possible 'end', not a function.
the code under the line is part of the code after the problem. Why does it want me to put end there? shouldn't it be so it can do the next function?
6. Re: Requesting help again... as a beginner....
- Posted by DanM May 24, 2009
- 1007 views
- Last edited May 25, 2009
<snip>
Alright, thanks. Is there a way to copy the code out of the editor, so I don't have to retype it?
Which editor?
If it's the Euphoria "ed", then you have to go over to the left top of the cmd window, click on the icon there, select first "edit", then "mark", use the cursor to mark the section you want to copy, then go back to that icon at the top left, select "edit" and then "copy"; that will put the marked portion into the "clipboard",(you have to make sure to go as far to the right side as necessary, to get full extent of all lines), then here in a post just press <ctl>V to put what you copied into a post here.
Anyways, heres what I got so far, but I have this ex.err that keeps saying I should have end instead. Heres just the segment of it that it reads up to.
sequence t integer h, e t = {1,10000} while t = {1,10000} do t = prompt_number("\nPlease enter a positive odd number.") if t <= 2 then puts(1,"\nThat is an unusable number.") t = {1,10000} else t = and_bits(t,1) power(t,2) = h ____________________ puts(1,h)
(I didn't know how to indent in eucode) The ex.err shows
power(t,2) = h
^ is under r at power.
expected to see possible 'end', not a function.
the code under the line is part of the code after the problem. Why does it want me to put end there? shouldn't it be so it can do the next function?
power is a function, not a procedure, your code there needs to be:
h = power(t,2)
I'm not sure if it's adequate to have "h" be an integer, though, because you could be raising decimal fractions to a power, and the result of that won't be integer type. So maybe you need "h" to be atom, I'm not sure.
Dan
7. Re: Requesting help again... as a beginner....
- Posted by doncole2009 May 24, 2009
- 980 views
- Last edited May 25, 2009
Hello Mattymatt,
To indent you code it would depend on which editor you are using, See the docs for you editor.
To indent in euphoria:
puts(1,repeat(" ",6)&"hello")
or
puts(1,"\t hello")\t is tab
As for your code you have a while and a for loop not closed.
Your code should be:
procedure whatever()--open procedure while t = {1,10000} do --open while loop if t <= 2 then --open if loop --your stuff end if --close if loop end while --close while loop end procedure--close procedure
don cole
8. Re: Requesting help again... as a beginner....
- Posted by Mattymatt May 24, 2009
- 995 views
- Last edited May 25, 2009
power is a function, not a procedure, your code there needs to be:
h = power(t,2)
I'm not sure if it's adequate to have "h" be an integer, though, because you could be raising decimal fractions to a power, and the result of that won't be integer type. So maybe you need "h" to be atom, I'm not sure.
Dan
Also, i'm doing this in .exw but I think I mentioned that before.
Okay, changed, but it keeps saying true/false condition must be an ATOM. I have changed h and e to atoms though. in the ex.err it says
6 true/false condition must be an ATOM
C:\EUPHORIA\include\get.e: input_file = <no value> input_string = <no value> string_next = <no value> ch = <no value>
t = {1,10000} h = <no value> e = <no value>
I tried adding an atom k = 10000 and using that to make t = {1,k}, and changing t to k, for the prompt number. something like k = prompt_number("\nsomething",t), but that didn't work either, its became basically the same ex.err file, but it would be 7 true/fals condition must be an ATOM, and added k = 10000.
Can anyone help?
9. Re: Requesting help again... as a beginner....
- Posted by jimcbrown (admin) May 24, 2009
- 956 views
- Last edited May 25, 2009
Anyways, heres what I got so far, but I have this ex.err that keeps saying I should have end instead. Heres just the segment of it that it reads up to.
sequence t integer h, e t = {1,10000} while t = {1,10000} do t = prompt_number("\nPlease enter a positive odd number.") if t <= 2 then puts(1,"\nThat is an unusable number.") t = {1,10000} else t = and_bits(t,1) power(t,2) = h ____________________ puts(1,h)
The ex.err shows <eucode> power(t,2) = h</eucode>
^ is under r at power.
expected to see possible 'end', not a function.
the code under the line is part of the code after the problem. Why does it want me to put end there? shouldn't it be so it can do the next function?
Try working with this code:
sequence range atom h, e, t range = {1,10000} t = -1 while 1 do t = prompt_number("\nPlease enter a positive odd number.", range) if t <= 2 then puts(1,"\nThat is an unusable number.") else t = and_bits(t,1) h = power(t,2) printf(1, "%d\n", {h}) end if end while
10. Re: Requesting help again... as a beginner....
- Posted by Mattymatt May 25, 2009
- 972 views
Try working with this code:
sequence range atom h, e, t range = {1,10000} t = -1 while 1 do t = prompt_number("\nPlease enter a positive odd number.", range) if t <= 2 then puts(1,"\nThat is an unusable number.") else t = and_bits(t,1) h = power(t,2) printf(1, "%d\n", {h}) end if end while
You. Rock. The program actually starts! For me, thats a big leap forward. However, there are a few areas that are confusing to me. Why does t = -1 need to be there? I deleted that and it still works. Just so I know, in <eucode> while 1 do </eucode> means 1 means true? Because I changed the number, and that still works.
The only faulty up part is when I put in a number, I always get back a 1 or 0. I want it so I get back the number by the power of 2. 1 means true if I remember, and 0 means false.... but, I was while I was messing with it, I think I got a 0.5 somehow, I don't remember what I put though. Shouldn't printf(1, "%d\n", {h}) show h instead of one, say if I typed in 5, it should return 25? I tried print(), puts(), messed with t = 1 in the beginning, and while.
11. Re: Requesting help again... as a beginner....
- Posted by DerekParnell (admin) May 25, 2009
- 974 views
Part of the problem is that we don't actually know what you are trying to do. I'm guessing now, that you want the user to enter an odd number and your program will calculate what the square of that number is, and then display the result. Is that it? If so, try this version ...
sequence range atom h, t range = {3,10000} while 1 do t = prompt_number("\nPlease enter a positive odd number greater than 2: ", range) if not and_bits(t,1) then puts(1,"\nThat is not an odd number, try again.") else h = power(t,2) printf(1, "%d squared is %d\n", {t,h}) end if end while
12. Re: Requesting help again... as a beginner....
- Posted by Mattymatt May 25, 2009
- 992 views
Part of the problem is that we don't actually know what you are trying to do. I'm guessing now, that you want the user to enter an odd number and your program will calculate what the square of that number is, and then display the result. Is that it? If so, try this version ...
sequence range atom h, t range = {3,10000} while 1 do t = prompt_number("\nPlease enter a positive odd number greater than 2: ", range) if not and_bits(t,1) then puts(1,"\nThat is not an odd number, try again.") else h = power(t,2) printf(1, "%d squared is %d\n", {t,h}) end if end while
Thanks, this helps a lot, I think I don't need anymore help, but if I do I'll come back and ask. Thanks everyone!
13. Re: Requesting help again... as a beginner....
- Posted by Mattymatt May 25, 2009
- 987 views
What is 'while 1 do'?
What does the 1 mean? Does it mean the condition is always true, so then 'while' would just keep looping just to clarify.
14. Re: Requesting help again... as a beginner....
- Posted by jimcbrown (admin) May 25, 2009
- 979 views
What is 'while 1 do'?
What does the 1 mean? Does it mean the condition is always true, so then 'while' would just keep looping just to clarify.
This is correct.
In short, 0 is false. Any integer or decimal point number that is not zero is true, i.e. -1 and 1 and 9 and 0.1 are all true.
15. Re: Requesting help again... as a beginner....
- Posted by euler May 25, 2009
- 985 views
It's amazing. No hints, no clues, no feedback at all. Just questions. 
16. Re: Requesting help again... as a beginner....
- Posted by DanM May 25, 2009
- 996 views
- Last edited May 26, 2009
What is 'while 1 do'?
What does the 1 mean? Does it mean the condition is always true, so then 'while' would just keep looping just to clarify.
this usage is an optimized form of the the "while some condition true, do the following, but exit when the condition is not true".
It's optimized in that in this form, it doesn't actually (as far as I know) check for any change in the status of the condition, but simply continuously loops. In such a case, you should usually provide some way to actually EXIT the loop, using the command "exit". Perhaps, allow user to input a zero, and if a zero is input, the command in the if statement would be "exit".
Dan
17. Re: Requesting help again... as a beginner....
- Posted by Mattymatt May 25, 2009
- 976 views
- Last edited May 26, 2009
It's amazing. No hints, no clues, no feedback at all. Just questions.
Hey man I'm still learning.
18. Re: Requesting help again... as a beginner....
- Posted by euler May 26, 2009
- 981 views
It's amazing. No hints, no clues, no feedback at all. Just questions.
Hey man I'm still learning.
Firstly, that's not the point, Mattymatt. Everyone here is willing to help, no complaints about asking questions, of any level, but you'd help us a lot (and also yourself) if you elaborate it a bit. Secondly, several fellows asked you simple questions and you answered to none. I find this sort of impolite. They are trying to refine which is the best answer, or just trying to find your needs, so you could at least answer their questions.
Again, this is a very helpful bunch of people. I'm here also to learn so, let's not spoil the help offered so kindly. My tuppence.
19. Re: Requesting help again... as a beginner....
- Posted by doncole2009 May 26, 2009
- 982 views
while 1 do
is the same as:
while 1=1 do
Don Cole
20. Re: Requesting help again... as a beginner....
- Posted by Mattymatt Jun 04, 2009
- 929 views
Part of the problem is that we don't actually know what you are trying to do. I'm guessing now, that you want the user to enter an odd number and your program will calculate what the square of that number is, and then display the result. Is that it? If so, try this version ...
sequence range atom h, t range = {3,10000} while 1 do t = prompt_number("\nPlease enter a positive odd number greater than 2: ", range) if not and_bits(t,1) then puts(1,"\nThat is not an odd number, try again.") else h = power(t,2) printf(1, "%d squared is %d\n", {t,h}) end if end while
Yes, that is what I was trying to do, then later I was going to add a formula to get another number. Just didn't want you guys to write the exact code, because then I would have done none of the work.
21. Re: Requesting help again... as a beginner....
- Posted by Mattymatt Jun 04, 2009
- 937 views
<snip>
Alright, thanks. Is there a way to copy the code out of the editor, so I don't have to retype it?
Which editor?
If it's the Euphoria "ed", then you have to go over to the left top of the cmd window, click on the icon there, select first "edit", then "mark", use the cursor to mark the section you want to copy, then go back to that icon at the top left, select "edit" and then "copy"; that will put the marked portion into the "clipboard",(you have to make sure to go as far to the right side as necessary, to get full extent of all lines), then here in a post just press <ctl>V to put what you copied into a post here.
Anyways, heres what I got so far, but I have this ex.err that keeps saying I should have end instead. Heres just the segment of it that it reads up to.
sequence t integer h, e t = {1,10000} while t = {1,10000} do t = prompt_number("\nPlease enter a positive odd number.") if t <= 2 then puts(1,"\nThat is an unusable number.") t = {1,10000} else t = and_bits(t,1) power(t,2) = h ____________________ puts(1,h)
(I didn't know how to indent in eucode) The ex.err shows
power(t,2) = h
^ is under r at power.
expected to see possible 'end', not a function.
the code under the line is part of the code after the problem. Why does it want me to put end there? shouldn't it be so it can do the next function?
power is a function, not a procedure, your code there needs to be:
h = power(t,2)
I'm not sure if it's adequate to have "h" be an integer, though, because you could be raising decimal fractions to a power, and the result of that won't be integer type. So maybe you need "h" to be atom, I'm not sure.
Dan
Yes, Euphoria editor. Okay, answered all the questions I could find, see anybody elses' euler?
22. Re: Requesting help again... as a beginner....
- Posted by Dan_M Jun 04, 2009
- 926 views
- Last edited Jun 05, 2009
<snipped>
Yes, Euphoria editor. Okay, answered all the questions I could find, see anybody elses' euler?
HUH? [insert confused face here]
Dan
23. Re: Requesting help again... as a beginner....
- Posted by Dan_M Jun 04, 2009
- 924 views
- Last edited Jun 05, 2009
<snipped>
Yes, Euphoria editor. Okay, answered all the questions I could find, see anybody elses' euler?
HUH? [insert confused face here]
Dan
Ok, never mind, I finally got it, you were responding to two different posts in one, and the other post was from euler. I spent a while googling and reading about Euler the mathematician, until my eyes crossed and I had to stop! 
Dan
