My assignment asks me to access a test.txt document, so the file name has to be hard coded to my C drive. I have no idea what hardcoding means. Can somebody please help me with this?
"hard coding" means putting something into your source code. If you are not hard coding, then you do something like prompting the user for the data, or allow the user to put the data on the command line, or something like that.
So, to hard code the location of the file as being on the C: drive, you would just put the pathname of the file all together in your source code.
Here is an example.
int main()
{
const char *filename = "C:\\myfile.txt";
printf("Filename is: %s\n", filename);
}
The file name is "hard coded" as: C:\myfile.txt
The reason the backslash is doubled is because backslashes are special in C strings.
"Hard Coding" means something that you want to embed with your program or any project that can not be changed directly.
For example, if you are using a database server, and hard code to connect your database with your project, then that can not be changed by the user.
Scenario
In a college there are many students doing different courses, and after an examination we have to prepare a marks card showing grade. I can calculate grade two ways
1. I can write some code like this
if(totalMark <= 100 && totalMark > 90) { grade = "A+"; }
else if(totalMark <= 90 && totalMark > 80) { grade = "A"; }
else if(totalMark <= 80 && totalMark > 70) { grade = "B"; }
else if(totalMark <= 70 && totalMark > 60) { grade = "C"; }
2. You can ask user to enter grade definition some where and save that data
Something like storing into a database table
In the first case the grade is common for all the courses and if the rule changes the code needs to be changed. But for second case we are giving user the provision to enter grade based on their requirement. So the code will be not be changed when the grade rules changes.
That's the important thing when you give more provision for users to define business logic. The first case is nothing but Hard Coding.
So in your question if you ask the user to enter the path of the file at the start, then you can remove the hard coded path in your code.
There are two types of coding.
(1) hard-coding
(2) soft-coding
Hard-coding. Assign values to program during writing source code and make executable file of program. Now, it is very difficult process to change or modify the program source code values. Like in block-chain technology, genesis block is hard-code that cannot changed or modified.
Soft-coding: it is process of inserting values from external source into computer program. Like insert values through keyboard, command line interface. Soft-coding considered as good programming practice because developers can easily modify programs.
Related
I'm fairly certain after years of searching that this is not possible, but I'll ask anyway.
The question is whether it's possible to use a dynamic variable in an operation when you don't know the field name. For example, I have a data structure that contains a few hundred fields. The operator selects one of those fields and the program needs to know what data resides in the field from the data structure passed. So we'll say that there are 100 fields, and field50 is what the operator chose to operate on. The program would be passed in the field name (i.e. field50) in the FLDNAM variable. The program would read something like this the normal way:
/free
if field50 = 'XXX'
// do something
endif;
/end-free
The problem is that I would have to code this 100 times for every operation. For example:
/free
if fldnam = 'field1';
// do something
elseif fldnam = 'field2';
// do something
..
elseif fldnam = 'field50';
// do something
endif;
Is there any possible way of performing an operation on a field not yet known? (i.e. IF FLDNAM(pointer data) = 'XXX' then do something)
If the data structure is externally-described and you know what file it comes from, you could use the QUSLFLD API to find out the offset, length, and type of the field in the data structure, and then use substring to get the data and then use other calculations to get the value, depending on the data type.
Simple answer, no.
RPG's simply not designed for that. Few languages are.
You may want to look at scripting languages. Perl for instance, can evaluate on the fly. REXX, which comes installed on the IBM i, has an INTERPRET keyword.
REXX Reference manual
A typical parser in Anorm looks a bit like this:
val idSeqParser: RowParser[IDAndSequence] = {
long("ID") ~
int("sequence") map {
case id ~ sequence => IDAndSequence(id, sequence)
}
}
Assuming of course that you had a case class like so:
case class IDAndSequence(id: Long, sequence: Int = 0)
All handy-dandy when you know this up front however what if you want to run ad-hoc queries (raw SQL) that you write at run time? (hint: an on the fly reporting engine)
How does one tackle that problem?
Can you create a series of generic parsers or various numbers of fields (which I see Scala itself had to resort to when processing tuples on Forms meaning you can only go to 22 elements in a form and unsure what the heck you do after that...)
You can assume that "everything is a string" for the purpose of reporting so Option[String] should cut it.
Can a parser be created on the fly however? If so what would doing that look like?
Is the a more elegant way to address this "problem"?
EDIT (to help clarify what I'm after)
As I could "ask" using aliases
Select f1 as 'a', f2 as 'b', f3 as 'c' from sometable
Then I could collect that with a pre-written parser like so
val idSeqParser: RowParser[IDAndSequence] = {
get[Option[String]]("a") ~
get[Option[String]]("b") ~
get[Option[String]]("c") map {
case a ~ b ~ c => GenericCase(a, b, c)
}
}
However that means I would need to de alias the columns for the actual report output. The suggestion of SqlParser.flatten already puts me ahead there as it has up to 22 (there's that "literal" kludge!) columns.
As I've written reports with greater than 22 columns in times past -- mostly as inputs to spreadsheets for further manual dat mining -- I would like to escape that limit if possible. Hard to tell a client you can't have that urgent 27 column report for 5 days but this 21 column one you can have in 5 minutes...
Going to try an experiment today to see if I can't find my own workable solution.
I'm using GameMaker:Studio Pro and trying to execute a script stored in a variable as below:
script = close_dialog;
script_execute(script);
It doesn't work. It's obviously looking for a script named "script". Anyone know how I can accomplish this?
This question's quite old now, but in case anyone else ends up here via google (as I did), here's something I found that worked quite well and avoids the need for any extra data structures as reference:
scriptToCall = asset_get_index(scr_scriptName);
script_execute(scriptToCall);
The first line here creates the variable scriptToCall and then assigns to it Game Maker's internal ID number for the script you want to call. This allows script_execute to correctly find the script from the ID, which doesn't work if you try to pass it a string containing the script name.
I'm using this to define which scripts should be called in a particular situation from an included txt file, hence the need to convert a string into an addressable script ID!
You seem to have some confusion over how Game Maker works, so I will try to address this before I get around to the actual question.
GML is a rather simple-minded beast, it only knows two data types: strings and numbers. Everything else (objects, sprites, scripts, data structures, instances and so on) is represented with a number in your GML code.
For example, you might have an object called "Player" which has all kinds of fancy events, but to the code Player is just a constant number which you can (e.g.) print out with show_message(string(Player));
Now, the function script_execute(script) takes as argument the ID of the script that should be executed. That ID is just a normal number. script_execute will find the script with that ID in some internal table and then run the script.
In other words, instead of calling script_execute(close_dialog) you could just as well call script_execute(14) if you happened to know that the ID of close_dialog is 14 (although that is bad practice, since it make the code difficult to understand and brittle against ID changes).
Now it should be obvious that assigning the numeric value of close_dialog to a variable first and then calling script_execute on that variable is perfectly OK. In the end, script_execute only cares about the number that is passed, not about the name of the variable that this number comes from.
If you are thinking ahead a bit, you might wonder whether you need script_execute at all then, or if you could instead just do this:
script = close_dialog;
script();
In my opinion, it would be perfectly fine to allow this in the language, but it does not work - the function call operator actually does care about the name of the thing you try to call.
Now with that background out of the way, on to your actual question. If close_dialog is actually a script, your suggested code will work fine. If it is an extension function (or a built-in function -- I don't own Studio so what do I know) then it does not actually have an ID, and you can't call it with script_execute. In fact, you can't even assign close_dialog to a variable then because it does not have any value in GML -- all you can do with it then is call it. To work around this though, you could create a script (say, close_dialog_script which only calls close_dialog, which you can then use just as above.
Edit: Since it does not seem to work anyway, check whether you have a different resource by the name of close_dialog (perhaps a button sprite). This kind of conflict could mean that close_dialog gives you the ID of the sprite, not of the script, while calling the script directly would still work.
After much discussion on the forums, I ended up going with this method.
I wrote a script called script_id()
var sid;
sid = 6; //6 = scriptnotfound script :)
switch (argument0) {
case "load_room":
sid = 0;
break;
case "show_dialog":
sid = 1;
break;
case "close_dialog":
sid = 3;
break;
case "scrExample":
sid = 4;
break;
}
return sid;
So now I can call script_execute(script_id("close_dialog"));
I hate it, but it's better than keeping a spreadsheet... in my opinion.
There's also another way, with execute_string();
Should look like this:
execute_string(string(scriptName) + "();");
I would like to create a plug-in necessary for our hospital, but I have never coded in Objective-C. I have been looking at many examples but cannot see how to select a specific word into a file to change it.
I want to select the word MRSC that is written on a line beginning with 0008,0060 and change it to MR (to tell our server that this file was sent by a MRI machine, which is necessary to archive it). I know how I can change the word, using NSMutableArray, but I don't know how to select my MRSC. How can I do this?
Something along these lines, assuming ARC or GC memory management:
NSString *inputLine = ... ; // the line you've read in
if ([inputLine hasPrefix:#"0008,0060") // is it a line needing changing?
{
// replace MRSC with MR and store result in same variable
inputLine = [inputLine stringByReplacingOccurencesOfString:#"MRSC" withString:#"MR"];
}
You could also do it with mutable strings if you wish, it makes little difference in this case.
When I´m using MATLAB, sometimes I feel the need to make comments on some variables. I would like to save these comments inside these variables. So when I have to work with many variables in the workspace, and I forget the context of some of these variables I could read the comments I put in every one of them. So I would like to comment variables and keep the comments inside of them.
While I'm of the opinion that the best (and easiest) approach would be to make your variables self-documenting by giving them descriptive names, there is actually a way for you to do what you want using the object-oriented aspects of MATLAB. Specifically, you can create a new class which subclasses a built-in class so that it has an additional property describing the variable.
In fact, there is an example in the documentation that does exactly what you want. It creates a new class ExtendDouble that behaves just like a double except that it has a DataString property attached to it which describes the data in the variable. Using this subclass, you can do things like the following:
N = ExtendDouble(10,'The number of data points')
N =
The number of data points
10
and N could be used in expressions just as any double value would. Using this example subclass as a template, you could create "commented" versions of other built-in numeric classes, with the exception of those you are not allowed to subclass (char, cell, struct, and function_handle).
Of course, it should be noted that instead of using the ExtendDouble class like I did in the above example, I could instead define my variable like so:
nDataPoints = 10;
which makes the variable self-documenting, albeit with a little more typing needed. ;)
How about declaring another variable for your comments?
example:
\>> num = 5;
\>> numc = 'This is a number that contains 5';
\>> whos
...
This is my first post in StackOverflow. Thanks.
A convenient way to solve this is to have a function that does the storing and displaying of comments for you, i.e. something like the function below that will pop open a dialog box if you call it with comments('myVar') to allow you to enter new (or read/update previous) comments to variable (or function, or co-worker) labeled myVar.
Note that the comments will not be available in your next Matlab session. To make this happen, you have to add save/load functionality to comments (i.e. every time you change anything, you write to a file, and any time you start the function and database is empty, you load the file if possible).
function comments(name)
%COMMENTS stores comments for a matlab session
%
% comments(name) adds or updates a comment stored with the label "name"
%
% comments prints all the current comments
%# database is a n-by-2 cell array with {label, comment}
persistent database
%# check input and decide what to do
if nargin < 1 || isempty(name)
printDatabase;
else
updateDatabase;
end
function printDatabase
%# prints the database
if isempty(database)
fprintf('no comments stored yet\n')
else
for i=1:size(database,1)
fprintf('%20s : %s\n',database{i,1},database{i,2});
end
end
end
function updateDatabase
%# updates the database
%# check whether there is already a comment
if size(database,1) > 0 && any(strcmp(name,database(:,1)))
idx = strcmp(name,database(:,1));
comment = database(idx,2);
else
idx = size(database,1)+1;
comment = {''};
end
%# ask for new/updated comment
comment = inputdlg(sprintf('please enter comment for %s',name),'add comment',...
5,comment);
if ~isempty(comment)
database{idx,1} = name;
database(idx,2) = comment;
end
end
end
Always always always keep the Matlab editor open with a script documenting what you do. That is, variable assignments and calculations.
Only exceptions are very short sessions where you want to experiment. Once you have something -- add it to the file (It's also easier to cut and paste when you can see your entire history).
This way you can always start over. Just clear all and rerun the script. You never have random temporaries floating around in your workspace.
Eventually, when you are finished, you will also have something that is close to 'deliverable'.
Have you thought of using structures (or cells, although structures would require extra memory use)?
'>> dataset1.numerical=5;
'>> dataset1.comment='This is the dataset that contains 5';
dataset1 =
numerical: 5
comment: 'This is the dataset that contains 5'