Search Results

Search found 9215 results on 369 pages for 'double pointers'.

facebook twitter digg google delicious technorati stumbleupon myspace wordpress linkedin gmail igoogle windows live tumblr viadeo yahoo buzz yahoo mail yahoo bookmarks favorites email print

Page 26/369 | < Previous Page | 22 23 24 25 26 27 28 29 30 31 32 33  | Next Page >

  • Compilation hangs for a class with field double d = 2.2250738585072012e-308

    - by 01es
    I have come across an interesting situation. A coworker committed some changes, which would not compile on my machine neither from the IDE (Eclipse) nor from a command line (Maven). The problem manifested in the compilation process taking 100% CPU and only killing the process would help to stop it. After some analysis the cause of the problem was located and resolved. It turned out be a line "double d = 2.2250738585072012e-308" (without semicolon at the end) in one of the interfaces. The following snipped duplicates it. public class WeirdCompilationIssue { double d = 2.2250738585072012e-308 } Why would compiler hang? A language edge case?

    Read the article

  • Why does C++ mandate that complex only be instantiated for float, double, or long double?

    - by templatetypedef
    According to the C++ ISO spec, §26.2/2: The effect of instantiating the template complex for any type other than float, double or long double is unspecified. Why would the standard authors explicitly add this restriction? This makes it unspecified, for example, what happens if you make complex<int> or a complex<MyCustomFixedPointType> and seems like an artificial restriction. Is there a reason for this limitation? Is there a workaround if you want to instantiate complex with your own custom type? I'm primarily asking this question because of this earlier question, in which the OP was confused as to why abs was giving bizarre outputs for complex<int>. That said, this still doesn't quite make sense given that we also might want to make complex numbers out of fixed-points types, higher-precision real numbers, etc. Thanks!

    Read the article

  • Array of strings and char ** environ variable.

    - by Naruto Uzumaki
    Hello! I want to know how an array of strings is declared? What I do is I declare an array of pointers of pointers to strings. Eg. char *array[]= {"string1","string2","string3"}; I was reading about modifying environment variables in Linux and stumbled upon the pointer char **environ ( http://www.cs.bham.ac.uk/resources/courses/2005/17423/doc/libc/Environment-Access.html#Environment-Access ). char **environ is declared as an array of strings. I think it should be a pointer to a pointer. For eg. char *array[]= {"string1","string2","string3"}; environ = array; Am I doing something wrong? I also read somewhere that char *argv[] = char **argv. How is it possible?

    Read the article

  • Perl Regular expression remove double tabs, line breaks, white spaces

    - by Scoox
    Hi guys, I want to write a perl script that removes double tabs, line breaks and white spaces. What I have so far is: $txt=~s/\r//gs; $txt=~s/ +/ /gs; $txt=~s/\t+/\t/gs; $txt=~s/[\t\n]*\n/\n/gs; $txt=~s/\n+/\n/gs; But, 1. It's not beautiful. Should be possible to do that with far less regexps. 2. It just doesn't work and I really do not know why. It leaves some double tabs, white spaces and empty lines (i.e. lines with only a tab or whitespace) I could solve it with a while, but that is very slow and ugly. Any suggestions?

    Read the article

  • In .net, how do I choose between a Decimal and a Double

    - by Ian Ringrose
    We were discussing this the other day at work and I wish there was a Stackoverflow question I would point people at so here goes.) What is the difference between a Double and a Decimal? When (in what cases) should you always use a Double? When (in what cases) should you always use a Decimal? What’s the diver factors to consider in cases that don’t fall into one of the two camps above? (There a lot of questions that overlap this question, but they tend to be asking what someone should do in a given case, not how to decide in the general case)

    Read the article

  • Safe to cast pointer to a forward-declared class to its true base class in C++?

    - by Matt DiMeo
    In one header file I have: #include "BaseClass.h" // a forward declaration of DerivedClass, which extends class BaseClass. class DerivedClass ; class Foo { DerivedClass *derived ; void someMethod() { // this is the cast I'm worried about. ((BaseClass*)derived)->baseClassMethod() ; } }; Now, DerivedClass is (in its own header file) derived from BaseClass, but the compiler doesn't know that at the time it's reading the definition above for class Foo. However, Foo refers to DerivedClass pointers and DerivedClass refers to Foo pointers, so they can't both know each other's declaration. First question is whether it's safe (according to C++ spec, not in any given compiler) to cast a derived class pointer to its base class pointer type in the absence of a full definition of the derived class. Second question is whether there's a better approach. I'm aware I could move someMethod()'s body out of the class definition, but in this case it's important that it be inlined (part of an actual, measured hotspot - I'm not guessing).

    Read the article

  • Distinguish between a single click and a double click in Java

    - by user552279
    Hi, I search the forum and see this codes: public void mouseClicked(MouseEvent e) { if (e.getClickCount() == 2) { System.out.println(" and it's a double click!"); wasDoubleClick = true; } else { Integer timerinterval = (Integer) Toolkit.getDefaultToolkit().getDesktopProperty( "awt.multiClickInterval"); timer = new Timer(timerinterval.intValue(), new ActionListener() { public void actionPerformed(ActionEvent evt) { if (wasDoubleClick) { wasDoubleClick = false; // reset flag } else { System.out.println(" and it's a simple click!"); } } }); timer.setRepeats(false); timer.start(); } } but the code runs incorrectly(Sometime it prints out " and it's a single click!" 2 times . It should print out " and it's a double click!"). Can anybody show me why? or can you give me some better ways to do this? Thank you!

    Read the article

  • C++ Pointer Issue

    - by Winder
    _stuckVertices is an array of pointers and I would like to update one index of that array without using _stuckVertices[ (row * _cols) + column ] 3 times. The reason it is an array of pointers is because the vast majority of the time the pointer will be NULL. The following code works but I need to dereference a each time I use it: void Cloth::stickPoint(int column, int row) { Anchor **a = &_stuckVertices[ (row * _cols) + column ]; if (!*a) *a = new Anchor(this, column, row); (*a)->stick(); } I originally had it written like this, but the _stuckVertices pointer doesn't get updated: void Cloth::stickPoint(int column, int row) { Anchor *a = _stuckVertices[ (row * _cols) + column ]; if (!a) a = new Anchor(this, column, row); a->stick(); } Is there a way to write Anchor *a = _stuckVertices[ index ] so that a is like an alias into the array that I can update, or is something like the first piece of code how I should do this? Thanks

    Read the article

  • Read from file into pointer to struct

    - by cla barzu
    I need help with pointers in C. I have to read from a file, and fill an array with pointers to struct rcftp_msg . Since now I did the next things: struct rcftp_msg { uint8_t version; uint8_t flags; uint16_t len; uint8_t buffer[512]; }; struct rcftp_msg *windows [10]; pfile = fopen(file,"r"); // Open the file I have to read from the file into the buffer, but I don't know how to do it. I tried the next: for (i = 0; i <10; i++){ leng=fread (**windows[i]->buffer**,sizeof(uint8_t),512,pfile); } I think windows[i]-buffer is bad, cuz that don't work. Sorry for my bad English :(

    Read the article

  • double returning only one precision in java

    - by srinath
    in my code i am performing division on numbers and storing it in a double variable. but the variable is returning with only one precision. i want to increase the precision how could i do that. double x; for ( int i =0 ; i<10000 ; i++) { x= w[i] / l[i]; System.out.println(x); } in the above code w and l are integer arrays; i am getting output like 3.0 0.0 1.0 0.0 i want to increase the precision upto 4 atleast.

    Read the article

  • Count double palindromes in given int sequence

    - by jakubmal
    For a given int sequence check number of double palindromes, where by double palindrome we mean sequence of two same palindromes without break between them. So for example: in 1 0 1 1 0 1 we have 1 0 1 as a palindrome which appears 2 times without a break, in 1 0 1 5 1 0 1 we have 1 0 1 but it's separated (apart from the other palindromes in these sequences) Problem example test data is: 3 12 0 1 1 0 0 1 1 0 0 1 1 0 12 1 0 1 0 1 0 1 0 1 0 1 0 6 3 3 3 3 3 3 with answers 8 0 9 Manacher is obvious for the begging, but I'm not sure what to do next. Any ideas appreciated. Complexity should be below n^2 I guess. EDIT: int is here treated as single element of alphabet

    Read the article

  • Java Double Array

    - by user1062058
    I'm having trouble setting up and placing values into an array using a text file containing the floating point numbers 2.1 and 4.3 each number is separated by a space - below is the error I'm getting: Exception in thread "main" java.util.NoSuchElementException import java.util.*; import java.io.*; public class DoubleArray { public static void main(String[] args) throws FileNotFoundException { Scanner in = new Scanner(new FileReader("mytestnumbers.txt")); double [] nums = new double[2]; for (int counter=0; counter < 2; counter++) { int index = 0; index++; nums[index] = in.nextDouble(); } } } Thanks, I'm sure this isn't a hard question to answer... I appreciate your time.

    Read the article

  • Preserving NULL values in a Double Variable

    - by Sam
    Hi, I'm working on a vb.net application which imports from an Excel spreadsheet. If rdr.HasRows Then Do While rdr.Read() If rdr.GetValue(0).Equals(System.DBNull.Value) Then Return Nothing Else Return rdr.GetValue(0) End If Loop Else I was using string value to store the double values and when preparing the database statement I'd use this code: If (LastDayAverage = Nothing) Then command.Parameters.AddWithValue("@WF_LAST_DAY_TAG", System.DBNull.Value) Else command.Parameters.AddWithValue("@WF_LAST_DAY_TAG", Convert.ToDecimal(LastDayAverage)) End If I now have some data with quite a few decimal places and the data was put into the string variable in scientific notation, so this seems to be the wrong approach. It didn't seem right using the string variable to begin with. If I use a double or decimal type variable, the blank excel values come across as 0.0. How can I preserve the blank values? Thanks

    Read the article

  • Type casting int into double C++

    - by user1705380
    I am new to programming and this might be an obvious question, though i cannot for life of me figure out why my program is not returning as a double. I am suppose to write a stocks program that takes in shares of stock, whole dollar portion of price and the fraction portion. And the fraction portion is to be inputted as two int values, and include a function definition with 3 int values.The function returns the price as a double. #include <iostream> using namespace std; int price(int, int, int); int main() { int dollars, numerator, denominator, price1, shares; char ans; do { cout<<"Enter the stock price and the number of shares.\n"; cout<<"Enter the price and integers: Dollars, numerator, denominator\n"; cin>>dollars>>numerator>>denominator; cout<<"Enter the number of shares held\n"; cin>>shares; cout<<shares; price1 = price(dollars,numerator,denominator); cout<<" shares of stock with market price of "; cout<< dollars << " " << numerator<<'/'<<denominator<<endl; cout<<"have a value of " << shares * price1<<endl; cout<<"Enter either Y/y to continue"; cin>>ans; }while (ans == 'Y' || ans == 'y'); system("pause"); return 0; } int price(int dollars, int numerator, int denominator) { return dollars + numerator/static_cast<double>(denominator); }

    Read the article

  • dimension || pointer pointer

    - by gcc
    What are pointers to pointers (like char **p;) used for? Can there be char ***p; or char ****p;? What would they be used for? my real question is >>what is the main purpose of char **p; why we need to use that type one answer is char *p - one dimension char *p - 2 dimensions char **p - 3 dimensions i have asked you can give example but he havenot answer i am thinking can we use ? is p[i][j] to **p that is can we use it like for(;;) for(;;) scanf("....",p[i][j]);

    Read the article

  • C++: Checking for non-numeric input and assigning to a double

    - by Brundle
    Here is the code I have at the moment: char ch; int sum = 0; double values[10]; int i = 0; cin >> ch; while (!isalpha(ch)) { values[i] = ch; sum += values[i]; i++; cin >> ch; } What is happening is that if I enter the value 1, that gets assigned to ch as a char. Now ch is assigning it's value to a double and doing an implicit cast. So it is assigning the ASCII value of '1' to values[i]. I want it to just assign 1 to values[i]. Is there a better way to do this? Or is there something that I'm missing?

    Read the article

  • Double "!!" in Ruby [closed]

    - by Alex Maslakov
    Possible Duplicate: What does !! mean in ruby? Ruby, !! operator (a/k/a the double-bang) Sometimes I see a Ruby code like this def sent? !!@sent_at end It seems to be not logical. Is it necessary to use here double !? As far as I'm concerned, it might be just def sent? @sent_at end UPDATE: then what is the difference between these def sent? !!@sent_at end def sent? @sent_at.nil? end def sent? @sent_at == nil end

    Read the article

  • How to overwrite an array of char pointers with a larger list of char pointers?

    - by Casey
    My function is being passed a struct containing, among other things, a NULL terminated array of pointers to words making up a command with arguments. I'm performing a glob match on the list of arguments, to expand them into a full list of files, then I want to replace the passed argument array with the new expanded one. The globbing is working fine, that is, g.gl_pathv is populated with the list of expected files. However, I am having trouble copying this array into the struct I was given. #include <glob.h> struct command { char **argv; // other fields... } void myFunction( struct command * cmd ) { char **p = cmd->argv; char* program = *p++; // save the program name (e.g 'ls', and increment to the first argument glob_t g; memset(&g, 0, sizeof(g)); g.gl_offs = 1; int res = glob(*p++, GLOB_DOOFFS, NULL, &g); glob_handle_res(res); while (*p) { res = glob(*p, GLOB_DOOFFS | GLOB_APPEND, NULL, &g); glob_handle_res(res); } if( g.gl_pathc <= 0 ) { globfree(&g); } cmd->argv = malloc((g.gl_pathc + g.gl_offs) * sizeof *cmd->argv); if (cmd->argv == NULL) { sys_fatal_error("pattern_expand: malloc failed\n");} // copy over the arguments size_t i = g.gl_offs; for (; i < g.gl_pathc + g.gl_offs; ++i) cmd->argv[i] = strdup(g.gl_pathv[i]); // insert the original program name cmd->argv[0] = strdup(program); ** cmd->argv[g.gl_pathc + g.gl_offs] = 0; ** globfree(&g); } void command_free(struct esh_command * cmd) { char ** p = cmd->argv; while (*p) { free(*p++); // Segfaults here, was it already freed? } free(cmd->argv); free(cmd); } Edit 1: Also, I realized I need to stick program back in there as cmd-argv[0] Edit 2: Added call to calloc Edit 3: Edit mem management with tips from Alok Edit 4: More tips from alok Edit 5: Almost working.. the app segfaults when freeing the command struct Finally: Seems like I was missing the terminating NULL, so adding the line: cmd->argv[g.gl_pathc + g.gl_offs] = 0; seemed to make it work.

    Read the article

  • Making Visual C++ DLL from C++ class

    - by prosseek
    I have the following C++ code to make dll (Visual Studio 2010). class Shape { public: Shape() { nshapes++; } virtual ~Shape() { nshapes--; }; double x, y; void move(double dx, double dy); virtual double area(void) = 0; virtual double perimeter(void) = 0; static int nshapes; }; class __declspec(dllexport) Circle : public Shape { private: double radius; public: Circle(double r) : radius(r) { }; virtual double area(void); virtual double perimeter(void); }; class __declspec(dllexport) Square : public Shape { private: double width; public: Square(double w) : width(w) { }; virtual double area(void); virtual double perimeter(void); }; I have the __declspec, class __declspec(dllexport) Circle I could build a dll with the following command CL.exe /c example.cxx link.exe /OUT:"example.dll" /DLL example.obj When I tried to use the library, Square* square; square->area() I got the error messages. What's wrong or missing? example_unittest.obj : error LNK2001: unresolved external symbol "public: virtual double __thiscall ... Square::area(void)" (?area@Square@@UAENXZ) ADDED Following wengseng's answer, I modified the header file, and for DLL C++ code, I added #define XYZLIBRARY_EXPORT However, I still got errors. example_unittest.obj : error LNK2019: unresolved external symbol "__declspec(dllimport) public: __th iscall Circle::Circle(double)" (__imp_??0Circle@@QAE@N@Z) referenced in function "protected: virtual void __thiscall TestOne::SetUp(void)" (?SetUp@TestOne@@MAEXXZ) example_unittest.obj : error LNK2019: unresolved external symbol "__declspec(dllimport) public: __th iscall Square::Square(double)" (__imp_??0Square@@QAE@N@Z) referenced in function "protected: virtual void __thiscall TestOne::SetUp(void)" (?SetUp@TestOne@@MAEXXZ) example_unittest.obj : error LNK2001: unresolved external symbol "public: virtual double __thiscall Square::area(void)" (?area@Square@@UAENXZ) example_unittest.obj : error LNK2001: unresolved external symbol "public: virtual double __thiscall Square::perimeter(void)" (?perimeter@Square@@UAENXZ) example_unittest.obj : error LNK2001: unresolved external symbol "public: virtual double __thiscall Circle::area(void)" (?area@Circle@@UAENXZ) example_unittest.obj : error LNK2001: unresolved external symbol "public: virtual double __thiscall Circle::perimeter(void)" (?perimeter@Circle@@UAENXZ)

    Read the article

  • Recording/Reading C doubles in the IEEE 754 interchange format

    - by rampion
    So I'm serializing a C data structure for cross-platform use, and I want to make sure I'm recording my floating point numbers in a cross-platform manner. I had been planning on just doing char * pos; /*...*/ *((double*) pos) = dataStructureInstance->fieldWithOfTypeDouble; pos += sizeof(double); But I wasn't sure that the bytes would be recorded in the char * array in the IEEE 754 interchange format. I've been bitten by cross-platform issues before (endian-ness and whatnot). Is there anything I need to do to a double to get the bytes in interchange format?

    Read the article

  • double_t in C99

    - by yCalleecharan
    Hi, I just read that C99 has double_t which should be at least wide as double. Does this imply that it gives more precision digits after the decimal place? More than the usual 15 digits for double?. Secondly, how to use it: Is only including #include enough? I read that one has to set the FLT_EVAL_METHOD to 2 for long double. How to do this? As I work with numerical methods, I would like maximum precision without using an arbitrary precision library. Thanks a lot...

    Read the article

facebook twitter digg google delicious technorati stumbleupon myspace wordpress linkedin gmail igoogle windows live tumblr viadeo yahoo buzz yahoo mail yahoo bookmarks favorites email print

< Previous Page | 22 23 24 25 26 27 28 29 30 31 32 33  | Next Page >