printf("* What is your age: xxx *)
scanf("%d", &age);
Is there a way I change the order the way it is executed. The xxx is the place i want the age to be inputed, but i want the * at the end to be printed before i am prompted to enter a number. Currently it asks for the number on the next line.
The output i would like to see is like the following:
What is your age: (Input required)
(Notice the * is already printed while i am prompted for an input in a field before the *)
Please can someone show me how to rewrite this?
Sorry if this is confusing.
There is a very easy way to do this with a small problem. You can use your printf function in normal way.
printf("* What is your age: xxx *");
Since at this point the cursor is right side of last asterisk, you need to move it left side 5 time to bring it where the first x is.
If you are on Linux, \033[<N>D can be used to move cursor once to left.
(#ref http://www.tldp.org/HOWTO/Bash-Prompt-HOWTO/x361.html).
Once the cursor is on first x, you can use your scanf function to prompt for number. But there is probability that user enters more than 3 digits and that asterisk will be cleared which is a problem.
Related
I am new to LabVIEW and I am trying to read a code written in LabVIEW. The block diagram is this:
This is the program to input x and y functions into the voltage input. It is meant to give an input voltage in different forms (sine, heartshape , etc.) into the fast-steering mirror or galvano mirror x and y axises.
x and y function controls are for inputting a formula for a function, and then we use "evaluation single value" function to input into a daq assistant.
I understand that { 2*(|-Mpi|)/N }*i + -Mpi*pi goes into the x value. However, I dont understand why we use this kind of formula. Why we need to assign a negative value and then do the absolute value of -M*pi. Also, I don`t understand why we need to divide to N and then multiply by i. And finally, why need to add -Mpi again? If you provide any hints about this I would really appreciate it.
This is just a complicated way to write the code/formula. Given what the code looks like (unnecessary wire bends, duplicate loop-input-tunnels, hidden wires, unnecessary coercion dots, failure to use appropriate built-in 'negate' function) not much care has been given in writing it. So while it probably yields the correct results you should not expect it to do so in the most readable way.
To answer you specific questions:
Why we need to assign a negative value and then do the absolute value
We don't. We can just move the negation immediately before the last addition or change that to a subtraction:
{ 2*(|Mpi|)/N }*i - Mpi*pi
And as #yair pointed out: We are not assigning a value here, we are basically flipping the sign of whatever value the user entered.
Why we need to divide to N and then multiply by i
This gives you a fraction between 0 and 1, no matter how many steps you do in your for-loop. Think of N as a sampling rate. I.e. your mirrors will always do the same movement, but a larger N just produces more steps in between.
Why need to add -Mpi again
I would strongly assume this is some kind of quick-and-dirty workaround for a bug that has not been fixed properly. Looking at the code it seems this +Mpi*pi has been added later on in the development process. And while I don't know what the expected values are I would believe that multiplying only one of the summands by Pi is probably wrong.
I'm using MQL5 (my first code).
I want to use a script that uses MA, but first, I wanted to confirm the value to verify I'm doing correctly. Using a very basic code into script:
double x=0;
x = iMA(Symbol(),Period(),100,0,MODE_SMA,PRICE_CLOSE);
Alert("The actual MA from last 100 points of EURUSD actually is: " + x;
The expected value is near the actual price... 1.23456, but this function is returning 10.00000 or 11.0000.
I believe I'm missing something, and https://www.mql5.com/es/docs/indicators/ima helplink is not quite clear enough.
I already saw another similar function: MA[0] which seems to bring the moving average from specific candle, but, I don't know how to manage the Period range (100) or if is related to Close/Open variables on it. I didn't find any specific helplink to review.
Any ideas are very appreciated!!!
x should be int, it is a handler of the MA. So each indicator when created in MT5 receives its handler, and you can use it later to get what you need. If you need several MA's - create several handlers and give each of them different names (x1, x2 or add some sense). Expert advisors in the default build of MT5 are good examples on what to do.
The iMA function Returns the handle of a specified technical indicator, not the "moving average" value.
For example, to get the value of the Moving average you can use this (in MQ4):
EMA34Handler = iMA(NULL,0,34,0,MODE_EMA,PRICE_CLOSE);
EMA34Value = CopyBuffer(EMA34Handler, 0,0);
So, this should be an easy question for anyone who has used FORTH before, but I am a newbie trying to learn how to code this language (and this is a lot different than C++).
Anyways, I'm just trying to create a variable in FORTH called "Height" and I want a user to be able to input a value for "Height" whenever a certain word "setHeight" is called. However, everything I try seems to be failing because I don't know how to set up the variable nor how to grab user input and put it in the variable.
VARIABLE Height 5 ALLOT
: setHeight 5 ACCEPT ATOI CR ;
I hope this is an easy problem to fix, and any help would be greatly appreciated.
Thank you in advance.
Take a look at Rosettacode input/output examples for string or number input in FORTH:
String Input
: INPUT$ ( n -- addr n )
PAD SWAP ACCEPT
PAD SWAP ;
Number Input
: INPUT# ( -- u true | false )
0. 16 INPUT$ DUP >R
>NUMBER NIP NIP
R> <> DUP 0= IF NIP THEN ;
A big point to remember for your self-edification -- C++ is heavily typecasted, Forth is the complete opposite. Do you want Height to be a string, an integer, or a float, and is it signed or unsigned? Each has its own use cases. Whatever you choose, you must interact with the Height variable with the type you choose kept in mind. Think about what your bits mean every time.
Judging by your ATOI call, I assume you want the value of Height as an integer. A 5 byte integer is unusual, though, so I'm still not certain. But here goes with that assumption:
VARIABLE Height 1 CELLS ALLOT
VARIABLE StrBuffer 7 ALLOT
: setHeight ( -- )
StrBuffer 8 ACCEPT
DECIMAL ATOI Height ! ;
The CELLS call makes sure you're creating a variable with the number of bits your CPU prefers. The DECIMAL call makes sure you didn't change to HEX somewhere along the way before your ATOI.
Creating the StrBuffer variable is one of numerous ways to get a scratch space for strings. Assuming your CELL is 16-bit, you will need a maximum of 7 characters for a zero-terminated 16-bit signed integer -- for example, "-32767\0". Some implementations have PAD, which could be used instead of creating your own buffer. Another common word is SCRATCH, but I don't think it works the way we want.
If you stick with creating your own string buffer space, which I personally like because you know exactly how much space you got, then consider creating one large buffer for all your words' string handling needs. For example:
VARIABLE StrBuffer 201 ALLOT
This also keeps you from having to make the 16-bit CELL assumption, as 200 characters easily accommodates a 64-bit signed integer, in case that's your implementation's CELL size now or some day down the road.
I am having difficulty understanding why the following code is giving me the numbers below. Can anyone explain this conversion from float to int? (pCLocation is a CGPoint)
counter = 0;
pathCells[counter][0].x = pCLocation.x;
pathCells[counter][0].y = pCLocation.y;
cellCount[counter]++;
NSLog(#"%#",[NSString stringWithFormat:#"pCLocation at:
%f,%f",pCLocation.x,pCLocation.y]);
NSLog(#"%#",[NSString stringWithFormat:#"path cell 0: %i,%i",
pathCells[counter][cellCount[counter-1]].x,pathCells[counter][cellCount[counter]].y]);
2012-03-09 01:17:37.165 50LevelsBeta1[1704:207] pCLocation at: 47.000000,16.000000
2012-03-09 01:17:37.172 50LevelsBeta1[1704:207] path cell 0: 0,1078427648
Assuming your code is otherwise correct:
I think it would help you to understand how NSLog and other printf-style functions work. When you call NSLog(#"%c %f", a_char, a_float), your code pushes the format string and values onto the stack, then jumps to the start of that function's code. Since NSLog accepts a variable number of arguments, it doesn't know how much to pop off the stack yet. It knows at least there is a format string, so it pops that off and begins to scan it. When it finds a format specifier %c, it knows to pop one byte off the stack and print that value. Then it finds %f, so now it knows to pop another 32 bits and print that as a floating point value. Then it reaches the end of the format string, so it's done.
Now here's the kicker: if you lie to NSLog and tell it you are providing a int but actually provide a float, it has no way to know you are lying. It simply assumes you are telling the truth and prints whatever bits it finds in memory however you asked it to be printed.
That's why you are seeing weird values: you are printing a floating point value as though it were an int. If you really want an int value, you should either:
Apply a cast: NSLog(#"cell.x: %i", (int)cell.x);
Leave it a float but use the format string to hide the decimals: NSLog(#"cell.x: %.0f", cell.x);
(Alternate theory, still potentially useful.)
You might be printing out the contents of uninitialized memory.
In the code you've given, counter = 0 and is never changed. So you assign values to:
pathCells[0][0].x = pCLocation.x;
pathCells[0][0].y = pCLocation.y;
cellCount[0]++;
Then you print:
pathCells[0][cellCount[-1]].x
pathCells[0][cellCount[0]].y
I'm pretty sure that cellCount[-1] isn't what you want. C allows this because even though you think of it as working with an array of a specific size, foo[bar] really just means grab the value at memory address foo plus offset bar. So an index of -1 just means take one step back. That's why you don't get a warning or error, just junk data.
You should clarify what pathCells, cellCount, and counter are and how they relate to each other. I think you have a bug in how you are combining these things.
This is my code:
x := 22 storeString.
y := x + x.
Transcript show: y.
Expected output: 2222
Actual output: 44.
I thought that the storeString message, sent to 22, assigned to x, would result in a string value being stored into x.
So I thought, I'm pretty new in smalltalk. Maybe it's order of operations? So I tried this:
x := (22 storeString).
y := x + x.
Transcript show: y.
Same result, and same, if I use printOn instead of storeOn. This is probably a day-one tutorial-following type question. But what is going on? Note that I know about the concatenation operator (,) but I am still wondering how it is that you can add two strings together like this? Is some implicit conversion from string back to integer happening as part of +?
Only a few things are implicit in Smalltalk. You can browse the implementation of #+ selector in String class and find out yourself what is going on. Or print String >> #+ definition.
You can also check out the internals of any running object instance, so you could have evaluated x inspect, to find out that x really is a String.
#+ is implemented on String and does a coercion to a Number before doing the addition.
Squeak has lot of eToys (a Smalltalk variation for kids) code spread throughout its core codebase. This is likely the reason why String implements all math operators. In Pharo the math operators have been mostly removed from String, so '1' + '2' raises an error like in any other Smalltalk.
Open a workspace. Enter:
'12' + '34'
Highlight and then use the right button menu to invoke "debug it". If ever there was a "killer app" for Smalltlak, it is the way the Smalltalk debugger interacts with the "all objects all the time" nature of Smalltalk. You can see what everything is and how it does. If you use "into", you'll be able to see exactly how it pulls off turning that into '46'.
Even cooler (I think), is that you can do
12 + '34'
(the first is no longer a string, rather a direct number). Again, you can use the debugger, and the whole double dispatch mechanism Smalltalk uses to do transcendental math will be opened up to you.
You can even do weirder examples like
4.0 + #('13' 2)
(here we're adding a number to an array, and the array contents are of mixed type)
Happy Smalltalking!
this behavior may appear puzzling to anyone not familiar with smalltalk, especially since in other languages the exact opposite tends to happen (numbers are coerced to strings).
the reason why this not a problem, is because string concatenation is done with ,. once aware of that, it becomes clear that '22' + 22 or even '22' + '22' can never be '2222'. it's either going to fail, or produce 44.
so if string concatenation is what you want, you need to send the right message:
x := 22 storeString.
y := x , x.
Transcript show: y.