Search Results

Search found 24721 results on 989 pages for 'int tostring'.

Page 122/989 | < Previous Page | 118 119 120 121 122 123 124 125 126 127 128 129  | Next Page >

  • Loading data from file to Vector structure

    - by owca
    I'm trying to parse through fixed-width formatted file extracting x,y values of points from it, and then storing them in int[] array inside a Vector. Text file looks as follows : 0006 0015 0125 0047 0250 0131 That's the code : Vector<int[]> vc = new Vector<int[]>(); try { BufferedReader file = new BufferedReader(new FileReader("myfile.txt")); String s; int[] vec = new int[2]; while ((s = file.readLine()) != null) { vec[0] = Integer.parseInt(s.substring(0, 4).trim()); vec[1] = Integer.parseInt(s.substring(5, 8).trim()); vc.add(vec); } file.close(); } catch (IOException e) { } for(int i=0; i<vc.size(); i++){ for(int j=0; j<2; j++){ System.out.println(vc.elementAt(i)[j]); } } But the output shows only last line. 250 131 250 131 250 131 Should I somehow use Vector.nextElement() here to get all my data ?

    Read the article

  • Entity and N-Tier architecture in C#

    - by acadia
    Hello, I have three tables as shown below Emp ---- empID int empName deptID empDetails ----------- empDetailsID int empID int empDocuments -------------- docID empID docName docType I am creating a entity class so that I can use n-tier architecture to do database transactions etc in C#. I started creating class for the same as shown below using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace employee { class emp { private int empID; private string empName; private int deptID; public int EmpID { get; set; } public string EmpName { get; set; } public int deptID { get; set; } } } My question is as empDetails and empDocuments are related to emp by empID. How do I have those in my emp class. I would appreciate if you can direct me to an example. Thanks

    Read the article

  • retrieve image from gallery in android

    - by smsys
    I have created an Activity where i have a Button. By pressing the button an android Gallery opens. When i choose an image from the gallery it is shows it in an ImageView of my Activity but after choosing second time the following error occuring 01-13 17:55:25.323: ERROR/AndroidRuntime(14899): java.lang.OutOfMemoryError: bitmap size exceeds VM budget Here is the source code i am using: public class MyImage extends Activity { /** Called when the activity is first created. */ Gallery gallery; private Uri[] mUrls; String[] mFiles=null; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); File images = Environment.getDataDirectory(); File[] imagelist = images.listFiles(); mFiles = new String[imagelist.length]; for(int i= 0 ; i< imagelist.length; i++) { mFiles[i] = imagelist[i].getAbsolutePath(); } mUrls = new Uri[mFiles.length]; for(int i=0; i < mFiles.length; i++) { mUrls[i] = Uri.parse(mFiles[i]); } Gallery g = (Gallery) findViewById(R.id.Gallery01); g.setAdapter(new ImageAdapter(this)); g.setFadingEdgeLength(40); } public class ImageAdapter extends BaseAdapter{ int mGalleryItemBackground; public ImageAdapter(Context c) { mContext = c; } public int getCount(){ return mUrls.length; } public Object getItem(int position){ return position; } public long getItemId(int position) { return position; } public View getView(int position, View convertView, ViewGroup parent){ ImageView i = new ImageView(mContext); i.setImageURI(mUrls[position]); i.setScaleType(ImageView.ScaleType.FIT_XY); i.setLayoutParams(new Gallery.LayoutParams(260, 210)); return i; } private Context mContext; } }

    Read the article

  • passing multidimensional arrays to function

    - by Pegah
    hi! I have a method in my class which uses a 3dimensional tfpairexp as input parameter. and I need to use the values in tfpairexp later. void calctfpairexp (int tf1, int tf2, double tfpairexp[][2][3]) { int ctr,c; for (int j = 0; j < cchips && (c = chips[j].crepls); j += c) { int ctrl_no=0; for (int *p = chips[j].ctrl ; p && (ctr=*p)>=0; ++p,ctrl_no++) { for (int k = 0; k < c; ++k) { tfpairexp[j][ctrl_no][k]=interactionFunc(2,3,1); } } } } I call the method inside the class like this: calctfpairexp(tf1,tf2,tfpairexp); and I need to use values inside tfpairexp in next lines. but the compiler gives error in this line: tfpairexp[j][ctrl_no][k]=interactionFunc(2,3,1); and says that the tfpairexp variable is not defined in the calctfpairexp function. any idea?

    Read the article

  • C++ Multiple Inheritance Question

    - by John
    The scenario generating this is quite complex so I'll strip out a few pieces and give an accurate representation of the classes involved. /* This is inherited using SI by many classes, as normal */ class IBase { virtual string toString()=0; }; /* Base2 can't inherit IBase due to other methods on IBase which aren't appropriate */ class Base2 { string toString() { ... } }; /* a special class, is this valid? */ class Class1 : public IBase, public Base2 { }; So, is this valid? Will there be conflicts on the toString? Or can Class1 use Base2::toString to satisfy IBase? Like I say there are lots of other things not shown, so suggestions for major design changes on this example are probably not that helpful... though any general suggestions/advice are welcome.

    Read the article

  • Behavior of virtual function in C++

    - by Summer_More_More_Tea
    Hi everyone: I have a question, here are two class below: class Base{ public: virtual void toString(); // generic implementation } class Derive : public Base{ public: ( virtual ) void toString(); // specific implementation } The question is: If I wanna subclass of class Derive perform polymophism using a pointer of type Base, is keyword virtual in the bracket necessary? If the answer is no, what's the difference between member function toString of class Derive with and without virtual?

    Read the article

  • How can I find all items beginning with a or â?

    - by Malcolm Frexner
    I have a list of items that are grouped by their first letter. By clicking a letter the user gets alle entries that begin with that letter. This does not work for french. If I choose the letter a, items with â are not returned. What is a good way to return items no matter if they have an accent or not? <% char alphaStart = Char.Parse("A"); char alphaEnd = Char.Parse("Z"); %> <% for (char i = alphaStart; i <= alphaEnd; i++) { %> <% char c = i; %> <% var abcList = Model.FaqList.Where(x => x.CmsHeader.StartsWith(c.ToString())).ToList(); %> <% if (abcList.Count > 0 ) { %> <div class="naviPkt"> <a id="<%= i.ToString().ToUpper() %>" class="naviPktLetter" href="#<%= i.ToString().ToLower() %>"><%= i.ToString().ToUpper() %></a> </div> <ul id="menuGroup<%= i.ToString().ToUpper() %>" class="contextMenu" style="display:none;"> <% foreach (var info in abcList) { %> <li class="<%= info.CmsHeader%>"> <a id="infoId<%= info.CmsInfoId%>" href="#<%= info.CmsInfoId%>" class="abcEntry"><%= info.CmsHeader%></a> </li> <% } %> </ul> <% } %> <% } %>

    Read the article

  • Mono & DeflateStream

    - by ILya
    I have a simple code byte[] buffer = Encoding.UTF8.GetBytes("abracadabra"); MemoryStream ms = new MemoryStream(); DeflateStream ds = new DeflateStream(ms, CompressionMode.Compress, false); ms.Write(buffer, 0, buffer.Length); DeflateStream ds2 = new DeflateStream(ms, CompressionMode.Decompress, false); byte[] buffer2 = new byte[ms.Length]; ds2.Read(buffer2, 0, (int)ms.Length); Console.WriteLine(Encoding.UTF8.GetString(buffer2)); And when reading from ds2, i have the following: Stacktrace: at (wrapper managed-to-native) System.IO.Compression.DeflateStream.ReadZStream (intptr,intptr,int) <0x00004 at (wrapper managed-to-native) System.IO.Compression.DeflateStream.ReadZStream (intptr,intptr,int) <0x00004 at System.IO.Compression.DeflateStream.ReadInternal (byte[],int,int) [0x00031] in C:\cygwin\tmp\monobuild\build\BUILD\mono-2.6.3\mcs\class\System\System.IO.Compression\DeflateStream.cs:192 at System.IO.Compression.DeflateStream.Read (byte[],int,int) [0x00086] in C:\cygwin\tmp\monobuild\build\BUILD\mono-2.6.3\mcs\class\System\System.IO.Compression\DeflateStream.cs:214 at testtesttest.MainClass.Main (string[]) [0x00041] in C:\Users\ilukyanov\Desktop\Cassini\GZipDemo\Main.cs:27 at (wrapper runtime-invoke) .runtime_invoke_void_object (object,intptr,intptr,intptr) This application has requested the Runtime to terminate it in an unusual way. Please contact the application's support team for more information. This problem appears in Mono 2.6.1 & 2.6.3... Is there any known way to successfully read from DeflateStream in Mono? Or maybe there are some third-party open-source assemblies with the same functionality?

    Read the article

  • Accesing Label.text in DataList

    - by Itay Gurvich
    So im trying to access informtaion from a label inside the DataList by pressing a button inside it. I put a code in thusly: protected void DataList1_SelectedIndexChanged(object sender, EventArgs e) { Character character = (Character)Session["character"]; Label lbl = (Label)DataList1.SelectedItem.FindControl("lblName"); int SkillID = int.Parse(DAL.ExecuteScalar("SELECT SkillID FROM skills WHERE SkillName = '" + lbl.ToString() + "'").ToString()); DAL.ExecuteNonQuery("INSERT INTO AssignedSkills (Offensive) Values ('" + SkillID.ToString() + "') WHERE CharID = '" + character.get_name().ToString() + "'"); } when i press the button its not even getting there and im getting an error "Invalid postback or callback argument." how can i access it?

    Read the article

  • Visual C++ 2010, rvalue reference bug?

    - by Sergey Shandar
    Is it a bug in Visual C++ 2010 or right behaviour? template<class T> T f(T const &r) { return r; } template<class T> T f(T &&r) { static_assert(false, "no way"); return r; } int main() { int y = 4; f(y); } I thought, the function f(T &&) should never be called but it's called with T = int &. The output: main.cpp(10): error C2338: no way main.cpp(17) : see reference to function template instantiation 'T f<int&>(T)' being compiled with [ T=int & ] Update 1 Do you know any C++x0 compiler as a reference? I've tried comeau online test-drive but could not compile r-value reference. Update 2 Workaround (using SFINAE): #include <boost/utility/enable_if.hpp> #include <boost/type_traits/is_reference.hpp> template<class T> T f(T &r) { return r; } template<class T> typename ::boost::disable_if< ::boost::is_reference<T>, T>::type f(T &&r) { static_assert(false, "no way"); return r; } int main() { int y = 4; f(y); // f(5); // generates "no way" error, as expected. }

    Read the article

  • Possible for C++ template to check for a function's existence?

    - by andy
    Is it possible to write a C++ template that changes behavior depending on if a certain member function is defined on a class? Here's a simple example of what I would want to write: template<class T> std::string optionalToString(T* obj) { if (FUNCTION_EXISTS(T->toString)) return obj->toString(); else return "toString not defined"; } So if class T has "toString" defined then it uses it, otherwise it doesn't. The magical part that I don't know how to do is the "FUNCTION_EXISTS" part.

    Read the article

  • How do i convert from milliseconds to seconds units to be shown in a Label?

    - by Doron Muzar
    I have this code: private void Form1_MouseWheel(object sender, MouseEventArgs e) { if (leave == true) { if (e.Delta > 0) { if (timer1.Interval < 5000) { timer1.Interval += 1000; label2.Text = (timer1.Interval/1000).ToString(); } } else { if (timer1.Interval == 1000) { timer1.Interval -= 100; label2.Text = (timer1.Interval / 1000).ToString(); } } } } The original timer1 interval in the designer is set to 1000 milliseconds. In the mouse wheel event i did that it will show in the label2 the untis in seconds. And indeed when i move the mouse wheel up its slowing the timer and show it in seconds 1 2 3 4 5 The problem is with the second part i wanted that when its getting to 1 second or 1000 milliseconds if i will keep wheel it down it will show the units in 100 and change the timer1.interval in 100 units. So in label2 if it was on 1 second so now i will see 900 800 700 600 500 un till 100. And also the timer1 interval should be change to 900 milliseconds 800 700 600 untill 100. When its get to 100 just stop there dont keep getting under 100. The problem is with this part: if (timer1.Interval == 1000) { timer1.Interval -= 100; label2.Text = (timer1.Interval / 1000).ToString(); } Its not working at all. EDIT** My code now: if (leave == true) { if (e.Delta > 0) { if (timer1.Interval < 5000) { timer1.Interval += 1000; label2.Text = (timer1.Interval / 1000).ToString(); } } else { if (timer1.Interval > 1000) { timer1.Interval -= 1000; label2.Text = (timer1.Interval / 1000).ToString(); } else if (timer1.Interval <= 1000 && timer1.Interval > 100) { timer1.Interval -= 100; label2.Text = (timer1.Interval / (double)1000).ToString(); } } } But now if i was at 5 seconds(5000 milliseconds) now i move the wheel back down its counting 5 4 3 2 1 0 and stop on 0 It dosent show under 1 ...0.9 0.8 0.7 as it did before.

    Read the article

  • clang does not compile but g++ does

    - by user1095108
    Can someone help me with this code: #include <type_traits> #include <vector> struct nonsense { }; template <struct nonsense const* ptr, typename R> typename std::enable_if<!std::is_void<R>::value, int>::type fo(void* const) { return 0; } template <struct nonsense const* ptr, typename R> typename std::enable_if<std::is_void<R>::value, int>::type fo(void* const) { return 1; } typedef int (*func_type)(void*); template <std::size_t O> void run_me() { static struct nonsense data; typedef std::pair<char const* const, func_type> pair_type; std::vector<pair_type> v; v.push_back(pair_type{ "a", fo<&data, int> }); v.push_back(pair_type{ "b", fo<&data, void> }); } int main(int, char*[]) { run_me<2>(); return 0; } clang-3.3 does not compile this code, but g++-4.8.1 does, which of the two compiler is right? Is something wrong with the code, as I suspect? The error reads: a.cpp:32:15: error: no matching constructor for initialization of 'pair_type' (aka 'pair<const char *const, func_type>') v.push_back(pair_type{ "a", fo<&data, int> }); ^ ~~~~~~~~~~~~~~~~~~~~~~~ a.cpp:33:15: error: no matching constructor for initialization of 'pair_type' (aka 'pair<const char *const, func_type>') v.push_back(pair_type{ "b", fo<&data, void> }); ^ ~~~~~~~~~~~~~~~~~~~~~~~~

    Read the article

  • How can i use listDictionary?

    - by Phsika
    i can fill my listdictinary but, if running error returns to me in " foreach (string ky in ld.Keys)"(invalid operation Exception was unhandled) Error Detail : After creating a pointer to the list of sample collection has been changed. C# ListDictionary ld = new ListDictionary(); foreach (DataColumn dc in dTable.Columns) { MessageBox.Show(dTable.Rows[0][dc].ToString()); ld.Add(dc.ColumnName, dTable.Rows[0][dc].ToString()); } foreach (string ky in ld.Keys) if (int.TryParse(ld[ky].ToString(), out QuantityInt)) ld[ky] = "integer"; else if(double.TryParse(ld[ky].ToString(), out QuantityDouble)) ld[ky]="double"; else ld[ky]="nvarchar";

    Read the article

  • to avoid page refresh during button click event in asp.net

    - by ush
    public partial class _Default : System.Web.UI.Page { protected void Page_Load(object sender, EventArgs e) { if (!IsPostBack) // If page loads for first time { Session["update"] = Server.UrlEncode(System.DateTime.Now.ToString()); // Assign the Session["update"] with unique value //=============== Page load code ========================= //============== End of Page load code =================== } } protected void Button1_Click(object sender, EventArgs e) { if (Session["update"].ToString() == ViewState["update"].ToString()) // If page not Refreshed { //=============== On click event code ========================= Label1.Text = TextBox1.Text; //lblDisplayAddedName.Text = txtName.Text; //=============== End of On click event code ================== // After the event/ method, again update the session Session["update"] = Server.UrlEncode(System.DateTime.Now.ToString()); } else // If Page Refreshed { // Do nothing } } protected override void OnPreRender(EventArgs e) { ViewState["update"] = Session["update"]; } } this is not working for high resolution gradient background

    Read the article

  • C#, wmi get disk manufacturer

    - by gloris
    Hi, how get USB flash(key) manufacturer name with C#? for example WD, Hama, Kingston... Now i with: "disk["Manufacturer"]", get: "Standard disk driver" string drive = "h"; ManagementObject disk = new ManagementObject("Win32_LogicalDisk.DeviceID=\"" + drive + ":\""); disk.Get(); Console.WriteLine(disk["VolumeSerialNumber"].ToString()); Console.WriteLine(disk["VolumeName"].ToString()); Console.WriteLine(disk["Manufacturer"].ToString());

    Read the article

  • Using an empty column as a divider in a JTable.

    - by Catalina Island
    I'm trying to use an empty column as a divider between pairs of columns in a JTable. Here's a picture and code for what I have so far. I know I can change the look using a custom TableCellRenderer. Before I go down that road, is there a better way to do this? Any ideas appreciated. import javax.swing.*; import javax.swing.table.*; public class TablePanel extends JPanel { public static void main(String[] args) { SwingUtilities.invokeLater(new Runnable() { @Override public void run() { JFrame f = new JFrame("TablePanel"); f.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE); f.add(new TablePanel()); f.pack(); f.setVisible(true); } }); } public TablePanel() { TableModel dataModel = new MyModel(); JTable table = new JTable(dataModel); table.getColumnModel().getColumn(MyModel.DIVIDER).setMaxWidth(0); JScrollPane jsp = new JScrollPane(table); jsp.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_ALWAYS); this.add(jsp); } private static class MyModel extends AbstractTableModel { private static final int DIVIDER = 2; private final String[] names = { "A1", "A2", "", "B1", "B2" }; @Override public int getRowCount() { return 32; } @Override public int getColumnCount() { return names.length; } @Override public String getColumnName(int col) { if (col == DIVIDER) return ""; return names[col]; } @Override public Object getValueAt(int row, int col) { if (col == DIVIDER) return ""; return (row + 1) / 10.0; } @Override public Class<?> getColumnClass(int col) { if (col == DIVIDER) return String.class; return Number.class; } } }

    Read the article

  • How can i create an n-dimensional array in c

    - by shortCircuit
    I was thinking of making a function that would accept the size of array as a parameter and create a n dimensional array. My room-mate took the liberty of making it complex. He said lets write a function that takes n parameters and returns an n-dimensional array using those parameters as the dimensions. Now i realize an one-day and d array is easy to implement with pointers. For 2d array the snippet would be something like (standard way) : int** x; int* temp; x = (int**)malloc(m * sizeof(int*)); temp = (int*)malloc(m*n * sizeof(int)); for (int i = 0; i < m; i++) { x[i] = temp + (i * n); } where the array is of size m*n; But the problem lies how do we find the nested loop parameters for a n-dimensional array? Is there any way to optimize the code?

    Read the article

  • Why won't this work; opencv Mat_<float>

    - by user1371674
    I can't seem to get this to work. I'm trying to get the pixel value of an image but first need to change the color of the image, but since I cannot use int or just Mat because the values are not whole numbers, I have to use and because of that errors pop up when I try to run this on the cmd. int main(int argc, char **argv) { Mat img = imread(argv[1]); ofstream myfile; Mat_<float> MatBlue = img; int rows1 = MatBlue.rows; int cols1 = MatBlue.cols; for(int x = 0; x < cols1; x++) { for(int y = 0; y < rows1; y++) { float val = MatBlue.at<cv::Vec3b>(y, x)[1]; MatBlue.at<cv::Vec3b>(y, x)[0] = val + 1; } } }

    Read the article

  • C struct written in file, open with Java

    - by DaunnC
    For example in C I have structure: typedef struct { int number; double x1; double y1; double x2; double y2; double x3; double y3; } CTRstruct;` Then I write it to file fwrite(&tr, 1, sizeof(tr), fp); (tr - its CTRstruct var, fp - File pointer); Then I need to read it with Java! I really don't know how to read struct from file... I tried to read it with ObjectInputStream(), last idea is to read with RandomAccessFile() but I also don't know how to... (readLong(), readDouble() also doesn't work, it works ofcource but doesn't read correct data). So, any idea how to read C struct from binary file with Java? If it's interesting, my version to read integer (but it's ugly, & I don't know what to do with double): public class MyDataInputStream extends DataInputStream{ public MyDataInputStream(InputStream AIs) { super(AIs); } public int readInt1() throws IOException{ int ch1 = in.read(); int ch2 = in.read(); int ch3 = in.read(); int ch4 = in.read(); if ((ch1 | ch2 | ch3 | ch4) < 0) throw new EOFException(); return ((ch4 << 24) + (ch3 << 16) + (ch2 << 8) + (ch1 << 0)); } with double we can deal the same way (like with int or with long (8bytes) & then convert to double with native func).

    Read the article

  • Defining a select list through controller and view model

    - by Ibrar Hussain
    I have a View Model that looks like this: public class SomeViewModel { public SomeViewModel(IEnumerable<SelectListItem> orderTemplatesListItems) { OrderTemplateListItems = orderTemplatesListItems; } public IEnumerable<SelectListItem> OrderTemplateListItems { get; set; } } I then have an Action in my Controller that does this: public ActionResult Index() { var items = _repository.GetTemplates(); var selectList = items.Select(i => new SelectListItem { Text = i.Name, Value = i.Id.ToString() }).ToList(); var viewModel = new SomeViewModel { OrderTemplateListItems = selectList }; return View(viewModel); } Lastly my view: @Html.DropDownListFor(n => n.OrderTemplateListItems, new SelectList(Model.OrderTemplateListItems, "value", "text"), "Please select an order template") The code works fine and my select list populates wonderfully. Next thing I need to do is set the selected value that will come from a Session["orderTemplateId"] which is set when the user selects a particular option from the list. Now after looking online the fourth parameter should allow me to set a selected value, so if I do this: @Html.DropDownListFor(n => n.OrderTemplateListItems, new SelectList(Model.OrderTemplateListItems, "value", "text", 56), "Please select an order template") 56 is the Id of the item that I want selected, but to no avail. I then thought why not do it in the Controller? As a final attempt I tried building up my select list items in my Controller and then passing the items into the View: public ActionResult Index() { var items = _repository.GetTemplates(); var orderTemplatesList = new List<SelectListItem>(); foreach (var item in items) { if (Session["orderTemplateId"] != null) { if (item.Id.ToString() == Session["orderTemplateId"].ToString()) { orderTemplatesList.Add(new SelectListItem { Text = item.Name, Value = item.Id.ToString(), Selected = true }); } else { orderTemplatesList.Add(new SelectListItem { Text = item.Name, Value = item.Id.ToString() }); } } else { orderTemplatesList.Add(new SelectListItem { Text = item.Name, Value = item.Id.ToString() }); } } var viewModel = new SomeViewModel { OrderTemplateListItems = orderTemplatesList }; return View(viewModel); } Leaving my View like so: @Html.DropDownListFor(n => n.OrderTemplateListItems, new SelectList(Model.OrderTemplateListItems, "value", "text"), "Please select an order template") Nothing! Why isn't this working for me?

    Read the article

  • Need help in Hashtable implementation

    - by rafael
    Hi all, i'm quite a beginner in C# , i tried to write a program that extract words from an entered string, the user has to enter a minimum length for the word to filter the words output ... my code doesn't look good or intuitive, i used two arrays countStr to store words , countArr to store word length corresponding to each word .. but the problem is i need to use hashtables instead of those two arrays , because both of their sizes are depending on the string length that the user enter , i think that's not too safe for the memory or something ? here's my humble code , again i'm trying to replace those two arrays with one hashtable , how can this be done ? using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Collections; namespace ConsoleApplication2 { class Program { static void Main(string[] args) { int i = 0 ; int j = 0; string myString = ""; int counter = 0; int detCounter = 0; myString = Console.ReadLine(); string[] countStr = new string[myString.Length]; int[] countArr = new int[myString.Length]; Console.Write("Enter minimum word length:"); detCounter = int.Parse(Console.ReadLine()); for (i = 0; i < myString.Length; i++) { if (myString[i] != ' ') { counter++; countStr[j] += myString[i]; } else { countArr[j] = counter; counter = 0; j++; } } if (i == myString.Length) { countArr[j] = counter; } for (i = 0; i < myString.Length ; i++) { if (detCounter <= countArr[i]) { Console.WriteLine(countStr[i]); } } Console.ReadLine(); } } }

    Read the article

  • whether rand_r is real thread safe?

    - by terry
    Well, rand_r function is supposed to be a thread safe function. However, by its implementation, I cannot believe it could make itself not change by other threads. Suppose that two threads will invoke rand_r in the same time with the same variable seed. So read-write race will occur. The code rand_r implemented by glibc is listed below. Anybody knows why rand_r is called thread safe? int rand_r (unsigned int *seed) { unsigned int next = *seed; int result; next *= 1103515245; next += 12345; result = (unsigned int) (next / 65536) % 2048; next *= 1103515245; next += 12345; result <<= 10; result ^= (unsigned int) (next / 65536) % 1024; next *= 1103515245; next += 12345; result <<= 10; result ^= (unsigned int) (next / 65536) % 1024; *seed = next; return result; }

    Read the article

  • SELECT product from subclass: How many queries do I need?

    - by Stefano
    I am building a database similar to the one described here where I have products of different type, each type with its own attributes. I report a short version for convenience product_type ============ product_type_id INT product_type_name VARCHAR product ======= product_id INT product_name VARCHAR product_type_id INT -> Foreign key to product_type.product_type_id ... (common attributes to all product) magazine ======== magazine_id INT title VARCHAR product_id INT -> Foreign key to product.product_id ... (magazine-specific attributes) web_site ======== web_site_id INT name VARCHAR product_id INT -> Foreign key to product.product_id ... (web-site specific attributes) This way I do not need to make a huge table with a column for each attribute of different product types (most of which will then be NULL) How do I SELECT a product by product.product_id and see all its attributes? Do I have to make a query first to know what type of product I am dealing with and then, through some logic, make another query to JOIN the right tables? Or is there a way to join everything together? (if, when I retrieve the information about a product_id there are a lot of NULL, it would be fine at this point). Thank you

    Read the article

  • pointer to a pointer in a linked list

    - by user1596497
    I'm trying to set a linked list head through pointer to a pointer. I can see inside the function that the address of the head pointer is changing but as i return to the main progran it becomes NULL again. can someone tell me what I'm doing wrong ?? #include <stdio.h> #include <stdlib.h> typedef void(*fun_t)(int); typedef struct timer_t { int time; fun_t func; struct timer_t *next; }TIMER_T; void add_timer(int sec, fun_t func, TIMER_T *head); void run_timers(TIMER_T **head); void timer_func(int); int main(void) { TIMER_T *head = NULL; int time = 1; fun_t func = timer_func; while (time < 1000) { printf("\nCalling add_timer(time=%d, func=0x%x, head=0x%x)\n", time, func, &head); add_timer(time, func, head); time *= 2; } run_timers(&head); return 0; } void add_timer(int sec, fun_t func, TIMER_T *head) { TIMER_T ** ppScan=&head; TIMER_T *new_timer = NULL; new_timer = (TIMER_T*)malloc(sizeof(TIMER_T)); new_timer->time = sec; new_timer->func = func; new_timer->next = NULL; while((*ppScan != NULL) && (((**ppScan).time)<sec)) ppScan = &(*ppScan)->next; new_timer->next = *ppScan; *ppScan = new_timer; }

    Read the article

< Previous Page | 118 119 120 121 122 123 124 125 126 127 128 129  | Next Page >