Search Results

Search found 42453 results on 1699 pages for 'question'.

Page 98/1699 | < Previous Page | 94 95 96 97 98 99 100 101 102 103 104 105  | Next Page >

  • a newbie gcc compiler and c language question

    - by dydx
    Hi, when I'm trying to compile my c program it gives me this error warning: integer constant is too large for 'long' type which refers to these lines int barcode, a, b, c; scanf("%d", &barcode); a = barcode / 1000000000000; b = barcode / 100000000000 % 10; c = barcode / 10000000000 % 10; and the rest is fine. I know I'm not supposed to use int for such a large number, any suggestions on what I should use? if I replace int with double what should the '%d' part be replaced with then?

    Read the article

  • C++ Memory allocation question involving vectors

    - by TheFuzz
    vector< int > vect; int *int_ptr = new int(10); vect.push_back( *int_ptr ); I under stand that every "new" needs to be followed by a "delete" at some point but does the clear() method clean this memory? What about this method of doing the same thing: vector< int > vect; int int_var = 10; vect.push_back( int_var ); From what I understand, clear() calls the variables destructors, but both vect.push_back() methods in this example push an object on the vector, not a pointer. so does the first example using an int pointer need something other than clear() to clean up memory?

    Read the article

  • Basic C question, concerning memory allocation and value assignment

    - by VHristov
    Hi there, I have recently started working on my master thesis in C that I haven't used in quite a long time. Being used to Java, I'm now facing all kinds of problems all the time. I hope someone can help me with the following one, since I've been struggling with it for the past two days. So I have a really basic model of a database: tables, tuples, attributes and I'm trying to load some data into this structure. Following are the definitions: typedef struct attribute { int type; char * name; void * value; } attribute; typedef struct tuple { int tuple_id; int attribute_count; attribute * attributes; } tuple; typedef struct table { char * name; int row_count; tuple * tuples; } table; Data is coming from a file with inserts (generated for the Wisconsin benchmark), which I'm parsing. I have only integer or string values. A sample row would look like: insert into table values (9205, 541, 1, 1, 5, 5, 5, 5, 0, 1, 9205, 10, 11, 'HHHHHHH', 'HHHHHHH', 'HHHHHHH'); I've "managed" to load and parse the data and also to assign it. However, the assignment bit is buggy, since all values point to the same memory location, i.e. all rows look identical after I've loaded the data. Here is what I do: char value[10]; // assuming no value is longer than 10 chars int i, j, k; table * data = (table*) malloc(sizeof(data)); data->name = "table"; data->row_count = number_of_lines; data->tuples = (tuple*) malloc(number_of_lines*sizeof(tuple)); tuple* current_tuple; for(i=0; i<number_of_lines; i++) { current_tuple = &data->tuples[i]; current_tuple->tuple_id = i; current_tuple->attribute_count = 16; // static in our system current_tuple->attributes = (attribute*) malloc(16*sizeof(attribute)); for(k = 0; k < 16; k++) { current_tuple->attributes[k].name = attribute_names[k]; // for int values: current_tuple->attributes[k].type = DB_ATT_TYPE_INT; // write data into value-field int v = atoi(value); current_tuple->attributes[k].value = &v; // for string values: current_tuple->attributes[k].type = DB_ATT_TYPE_STRING; current_tuple->attributes[k].value = value; } // ... } While I am perfectly aware, why this is not working, I can't figure out how to get it working. I've tried following things, none of which worked: memcpy(current_tuple->attributes[k].value, &v, sizeof(int)); This results in a bad access error. Same for the following code (since I'm not quite sure which one would be the correct usage): memcpy(current_tuple->attributes[k].value, &v, 1); Not even sure if memcpy is what I need here... Also I've tried allocating memory, by doing something like: current_tuple->attributes[k].value = (int *) malloc(sizeof(int)); only to get "malloc: * error for object 0x100108e98: incorrect checksum for freed object - object was probably modified after being freed." As far as I understand this error, memory has already been allocated for this object, but I don't see where this happened. Doesn't the malloc(sizeof(attribute)) only allocate the memory needed to store an integer and two pointers (i.e. not the memory those pointers point to)? Any help would be greatly appreciated! Regards, Vassil

    Read the article

  • A question of style/readability regarding the C# "using" statement

    - by Charles
    I'd like to know your opinion on a matter of coding style that I'm on the fence about. I realize there probably isn't a definitive answer, but I'd like to see if there is a strong preference in one direction or the other. I'm going through a solution adding using statements in quite a few places. Often I will come across something like so: { log = new log(); log.SomeProperty = something; // several of these log.Connection = new OracleConnection("..."); log.InsertData(); // this is where log.Connection will be used ... // do other stuff with log, but connection won't be used again } where log.Connection is an OracleConnection, which implements IDisposable. The neatnik in me wants to change it to: { log = new log(); using (OracleConnection connection = new OracleConnection("...")) { log.SomeProperty = something; log.Connection = conn; log.InsertData(); ... } } But the lover of brevity and getting-the-job-done-slightly-faster wants to do: { log = new log(); log.SomeProperty = something; using (log.Connection = new OracleConnection("...")) log.InsertData(); ... } For some reason I feel a bit dirty doing this. Do you consider this bad or not? If you think this is bad, why? If it's good, why?

    Read the article

  • C++: Short question regarding switch and break

    - by oh boy
    Example: switch( x ) { case y: if ( true ) { break; } cout << "Oops"; break; } If the switch statement selects y, will Oops be written to the standard output? - Is break in switch statements a dynamic keyword like continue which can be called under conditions or static like a closing bracket }?

    Read the article

  • List remove question

    - by younevertell
    List collCustList = new List(); collCustList.Add(new Customer(99, "H", "P")); I tried collCustList.Remove(new Customer(99, "H", "P")); but it doesn't work How could I remove the new item(new Customer(99, "H", "P")) I just added? Thanks

    Read the article

  • Python threading question (Working with a method that blocks forever)

    - by Nix
    I am trying to wrap a thread around some receiving logic in python. Basically we have an app, that will have a thread in the background polling for messages, the problem I ran into is that piece that actually pulls the messages waits forever for a message. Making it impossible to terminate... I ended up wrapping the pull in another thread, but I wanted to make sure there wasn't a better way to do it. Original code: class Manager: def __init__(self): receiver = MessageReceiver() receiver.start() #do other stuff... class MessageReceiver(Thread): receiver = Receiver() def __init__(self): Thread.__init__(self) def run(self): #stop is a flag that i use to stop the thread... while(not stopped ): #can never stop because pull below blocks message = receiver.pull() print "Message" + message What I refectored to: class Manager: def __init__(self): receiver = MessageReceiver() receiver.start() class MessageReceiver(Thread): receiver = Receiver() def __init__(self): Thread.__init__(self) def run(self): pullThread = PullThread(self.receiver) pullThread.start() #stop is a flag that i use to stop the thread... while(not stopped and pullThread.last_message ==None): pass message = pullThread.last_message print "Message" + message class PullThread(Thread): last_message = None def __init__(self, receiver): Thread.__init(self, target=get_message, args=(receiver)) def get_message(self, receiver): self.last_message = None self.last_message = receiver.pull() return self.last_message I know the obvious locking issues exist, but is this the appropriate way to control a receive thread that waits forever for a message? One thing I did notice was this thing eats 100% cpu while waiting for a message... **If you need to see the stopping logic please let me know and I will post.

    Read the article

  • mysql PHP query question

    - by camran
    Ok, i have a problem here... I am sending values of drop down lists via ajax to this PHP file. Now I want to search a mysql database using these values, which I have managed to do, BUT, only if I set the values to something... Take a look: $query = "SELECT * FROM cars_db WHERE price BETWEEN '$cars_price_from' AND '$cars_price_to' AND year BETWEEN '$cars_year_from' AND '$cars_year_to' AND mileage BETWEEN '$cars_mileage_from' AND '$cars_mileage_to' AND gearbox = '$cars_gearbox' AND fuel = '$cars_fuel'"; now, what if the user doesnt select any "price_from" or "year_from"... The fields are only optional, so if the user doesnt enter any "price from" or "year from", then the user wants ALL cars to show... Do I have to write a query statement for each case or is there another way?

    Read the article

  • c struct question

    - by lhw
    Hi, I'm trying to implement a simple priority queue from array of queues. I'm trying to define a struct queue, and than a struct priority queue that has an array of queues as its member variable. However, when I try to compile the code, I get the following error: pcb.h:30: error: array type has incomplete element type The code is below: typedef struct{ pcb *head; pcb *tail; SINT32 size; } pcb_Q; typedef struct { struct pcb_Q queues[5]; SINT32 size; } pcb_pQ; Could someone give me a hand? Thanks a lot.

    Read the article

  • C++ pointer to functions, Beginner Question...

    - by BobAlmond
    Hi all, I want to ask about pointer in C++ I have some simple code: int add(int a, int b){ return a+b; } int runner(int x,int y, int (*functocall)(int, int)){ return (*functocall)(x,y); } now, suppose I call those functions using this way : cout<<runner(2,5,&add); or maybe cout<<runner(2,5,add); is there any difference? because when I tried, the result is the same and with no error. Thanks a lot

    Read the article

  • Java Container constraints question

    - by llm
    I am using the following: java.awt.Container.add(Component comp, Object constraints) How do I specificy the constraints object? I need to be able to place a component within the container. Oh and my class extends JInternalFrame if this helps... I need to specify coordinates to place the component within the container

    Read the article

  • Beginner's Question about accessing mysql using OOP

    - by user345690
    I am reading the PHP and mySQL web development book and so far been doing all the PHP and mysql using procedural. But then it talks about accessing mysql with objects. This works for me: //I define $db so can connect $query="select * FROM testing"; $result=mysqli_query($db,$query); while($row=mysqli_fetch_array($result)){ //echo the data } But when I try to do it with classes, it doesn't $query="select * FROM testing"; $result=$db->query($query); $row=$result->fetch_assoc(); Do I have to write my own class so it defines what query and fetch_assoc does? Or what?

    Read the article

  • Twitter OAuth question

    - by Squall
    Hi there, I'm making a Twitter client in Java, and I've came to a problem I don't know how to solve it. How the hell I store open auth for twitter? I mean it doesn't make very sense for a person to allow an application every time he wants to use the client. I've been look at the Twitter documentation, but I must say, it's really poor in terms of Java. So do you guy have some idea to solve this? Thanks in advance!

    Read the article

  • Basic question on c++ header file inclusion ?

    - by siva
    What are the differences between below 3 programs ?. Is <iostream> a header file or C++ standard library ? 1 #include<iostream> using namespace std; int main() { return 0; } 2 #include<iostream> int main() { return 0; } 3 #include<iostream.h> int main() { return 0; } Thanks in advance.

    Read the article

  • Unable to import example projects from book (newbie question)

    - by StayWett
    I am trying to import projects from a book "Beginning Android 2" but when I choose the root directory the "Finish" button is still grayed out. I've tried importing the project from scratch with no success, and I've also tried to create a template project with the same name and everything and then importing into that (Import existing projects into workspace) but it always says "No projects are found to import". The contents of the folder are: Res folder, src folder with .java file, the manifest, build, and default.properties files. I am new to android dev (obviously) so I appreciate the help.

    Read the article

  • 2 Minute question - HTML / CSS If div within div expands expand parent div

    - by Ozaki
    I have a setup lets say like follows: <div id="nav"> <div id="innernav"> //With dynamic content here. </div> </div> I am running a script that sizes #nav to the size of the browser window in height. But sometimes my dynamic content is now getting bigger than the height of the window.. Is there a way I can enforce that when #innernav exceeds #nav that #nav will increase in size?

    Read the article

  • Question about JavaScript syntax

    - by Sakti
    $(document).ready(function(){ var date = new Date(); var d = date.getDate(); var m = date.getMonth(); var y = date.getFullYear(); var month = new array("January","February","March","April","May","June","July","August","September","October","November","December"); var mon; mon = month(m); var today = m+"/"+d+"/"+y $('#calendar').append('<div id="today">Today is'+' '+mon+'/'+d+'/'+y+'.'); });

    Read the article

  • Question about fwrite API

    - by michael
    Hi, In C++, there is a fwrite() which writes a buffer to a file on disk: http://www.cplusplus.com/reference/clibrary/cstdio/fwrite/ Can you please tell me if there is any buffer inside that fwrite implementation? i.e. if I call fwrite() multiple times (say 10 times), does it actually invoke file i/o 10 different times? Thank you.

    Read the article

  • Code casing question for private class fields

    - by user200295
    Take the following example public class Class1{ public string Prop1{ get {return m_Prop1;} set {m_Prop1 = value; } } private string m_Prop1; // this is standard private property variable name // how do we cap this variable name? While the compiler can figure out same casing // it makes it hard to read private Class2 Class2; // we camel case the parameter public Class1(Class2 class2){ this.Class2 = class2; } } Here are my stock rules The class name is capitalized (Class1) The public properties are capitalized (Prop1) The private field tied to a public property has m_ to indicate this. My coworker prefers _ There is some debate if using m_ or _ should be used at all, as it is like Hungarian notation. Private class fields are capitalized. The part I am trying to figure out is what do I do if when the Class name of a private field matches the private field name. For example, private Class2 Class2; This is confusing. If the private field name is not the same class, for example private string Name; , there isn't much issue. Or am I thinking about the issue wrong. Should my classes and private fields be named in such a way that they don't collide?

    Read the article

  • JSF templating beginner's question.

    - by Nitesh Panchal
    Hello, I belong to Asp.Net but just starting to learn JSF. I wanted to know whether all features of MasterPage are available in JSF templating? I mean say suppose i have a menu in template, and based on roles menu changes. If the Admin logs in, he will get to show more options and if general user logs in he will get to see less options. Now i have a managed bean for my "real" page(not template). How do i use this managed bean to toggle my control in template on and Off?

    Read the article

  • Beginner question about getting reference to cin

    - by John C
    I'm having problems wrapping my head around this. I have a function void foo(istream& input) { input = cin; } This fails (I'm assuming because cin isn't supposed to be "copyable". however, this works void foo(istream& input) { istream& baz = cin; } Is there a reason that I can get a reference to cin in baz but I cannot assign it to input? Thanks

    Read the article

< Previous Page | 94 95 96 97 98 99 100 101 102 103 104 105  | Next Page >