Search Results

Search found 2886 results on 116 pages for 'std'.

Page 82/116 | < Previous Page | 78 79 80 81 82 83 84 85 86 87 88 89  | Next Page >

• boost timer usage question

  - by stefita

  I have a really simple question, yet I can't find an answer for it. I guess I am missing something in the usage of the boost timer.hpp. Here is my code, that unfortunately gives me an error message: include <boost/timer.hpp> int main() { boost::timer t; } And the error messages are as follows: /usr/include/boost/timer.hpp: In member function ‘double boost::timer::elapsed_max() const’: /usr/include/boost/timer.hpp:59: error: ‘numeric_limits’ is not a member of ‘std’ /usr/include/boost/timer.hpp:59: error: ‘::max’ has not been declared /usr/include/boost/timer.hpp:59: error: expected primary-expression before ‘double’ /usr/include/boost/timer.hpp:59: error: expected `)' before ‘double’ The used library is boost 1.36 (SUSE 11.1). Thanks in advance!

  Read the article

• Why isn't the copy constructor elided here?

  - by Jesse Beder

  (I'm using gcc with -O2.) This seems like a straightforward opportunity to elide the copy constructor, since there are no side-effects to accessing the value of a field in a bar's copy of a foo; but the copy constructor is called, since I get the output meep meep!. #include <iostream> struct foo { foo(): a(5) { } foo(const foo& f): a(f.a) { std::cout << "meep meep!\n"; } int a; }; struct bar { foo F() const { return f; } foo f; }; int main() { bar b; int a = b.F().a; return 0; }

  Read the article

• Assigning unsigned char* buffer to a string

  - by CPPChase

  This question might be asked before but I couldn't find exactly what I need. My problem is, I have a buffer loaded by data downloaded from a webservice. The buffer is in unsigned char* form in which there is no '\0' at the end. Then I have a poco xml parser needs a string. I tried assigning it to string but now I realized it would cause problem such as leaking. here is the code: DOMParser::DOMParser(unsigned char* consatData, int consatDataSize, unsigned char* lagData, int lagDataSize) { Poco::XML::DOMParser parser; std::string consat; consat.assign((const char*) consatData, consatDataSize); pDoc = parser.parseString(consat); ParseConsat(); } Poco xml parser does have a ParseMemory which need a const char* and size of data but for some reason it just gives me segmentation fault. So I think it's safer to turn it to string. Thanks in advance.

  Read the article

• NSCoding and ostream

  - by Stephen Furlani

  Is there a better way to serialize an ObjC object than using /NSKeyedArchive? I need to distribute the object through a C++ std:ostream-like object to put on another computer. The object has over 122 members of various types... for which wants me to [coder encodeObject: (id) forKey: @"blah"]; for all of them... Does anyone have a nice Perl Script that will at least write it out? I don't even know if the objects it contains implement which means this could turn into a huge ugly mess since I can't change the source of the object - I'll have to inherit & add the @interface to it... Or am I being dumb? Apple's guide doesn't help me since archiving to XML won't pass nicely though the ostream. Is there a better way to do this? -S!

  Read the article

• C++ WIN32: Short multitasking example

  - by Con Current

  I searched for examples on how to create a simple multithreaded app that does something similar to this: #include <iostream> using namespace std; int myConcurrentFunction( ) { while( 1 ) { cout << "b" << endl; } } int main( ) { // Start a new thread for myConcurrentFunction while( 1 ) { cout << "a" << endl; } } How can I get the above to output a and b "randomly" by starting a new thread instead of just calling myConcurrentFunction normally? I mean: What is the minimal code for it? Is it really only one function I have to call? What files do I need to include? I use MSVC 2010, Win32

  Read the article

• C++ enumaration

  - by asli

  Hi,my question is about enumaration,my codes are : #include<iostream> using namespace std; int main() { enum bolumler{programcilik,donanim,muhasebe,motor,buro} bolum; bolum = donanim; cout<<bolum<<endl; bolum+=2; /* bolum=motor */ cout<<bolum; return 0; } The output should be 1 3 but according to these codes the error is: error C2676: binary '+=' : 'enum main::bolumler' does not define this operator or a conversion to a type acceptable to the predefined operator Error executing cl.exe. 111.obj - 1 error(s), 0 warning(s) Can you help me ?The other question is what can I do if I want to see the output like that "muhasebe"?

  Read the article

• Const Functions and Interfaces in C++

  - by 58gh1z

  I'll use the following (trivial) interface as an example: struct IObject { virtual ~IObject() {} virtual std::string GetName() const = 0; virtual void ChangeState() = 0; }; Logic dictates that GetName should be a const member function while ChangeState shouldn't. All code that I've seen so far doesn't follow this logic, though. That is, GetName in the example above wouldn't be marked as a const member function. Is this laziness/carelessness or is there a legitimate reason for this? What are the major cons of me forcing my clients to implement const member functions when they are logically called for?

  Read the article

• SQL Server float datatype

  - by Martin Smith

  The documentation for SQL Server Float says Approximate-number data types for use with floating point numeric data. Floating point data is approximate; therefore, not all values in the data type range can be represented exactly. Which is what I expected it to say. If that is the case though why does the following return 'Yes' in SQL Server DECLARE @D float DECLARE @E float set @D = 0.1 set @E = 0.5 IF ((@D + @D + @D + @D +@D) = @E) BEGIN PRINT 'YES' END ELSE BEGIN PRINT 'NO' END but the equivalent C++ program returns "No"? #include <iostream> using namespace std; int main() { float d = 0.1F; float e = 0.5F; if((d+d+d+d+d) == e) { cout << "Yes"; } else { cout << "No"; } }

  Read the article

• What is a cross-platform way to get the current directory?

  - by rubenvb

  I need a cross-platform way to get the current working directory (yes, getcwd does what I want). I thought this might do the trick: #ifdef _WIN32 #include <direct.h> #define getcwd _getcwd // stupid MSFT "deprecation" warning #elif #include <unistd.h> #endif #include <string> #include <iostream> using namespace std; int main() { string s_cwd(getcwd(NULL,0)); cout << "CWD is: " << s_cwd << endl; } I got this reading: _getcwd at MSDN getcwd at Kernel.org getcwd at Apple.com There should be no memory leaks, and is should work on a Mac as well, correct?

  Read the article

• Convert a number from string to integer without using inbuilt function

  - by Raja

  I am trying this technique but error is coming. Please help me to convert a number from string to integer. #include<iostream> using namespace std; int main() { char *buffer[80]; int a; cout<<"enter the number"; cin.get(buffer,79); char *ptr[80] = &buffer; while(*ptr!='\0') { a=(a*10)+(*ptr-48); } cout<<"the value"<<a; delete ptr[]; return 0; } Errors are: error C2440: 'initializing' : cannot convert from 'char ()[80]' to 'char *[80]' error C2440: '=' : cannot convert from 'char *' to 'int'

  Read the article

• Why do I get the error "X is not a member of Y" even though X is a friend of Y?

  - by user1232138

  I am trying to write a binary tree. Why does the following code report error C2039, "'<<' : is not a member of 'btree<T'" even though the << operator has been declared as a friend function in the btree class? #include<iostream> using namespace std; template<class T> class btree { public: friend ostream& operator<<(ostream &,T); }; template<class T> ostream& btree<T>::operator<<(ostream &o,T s) { o<<s.i<<'\t'<<s.n; return o; }

  Read the article

• Floating point innacuracies

  - by Greg

  While writing a function which will perform some operation with each number in a range I ran into some problems with floating point inaccuracies. The problem can be seen in the code below: #include <iostream> using namespace std; int main() { double start = .99999, end = 1.00001, inc = .000001; int steps = (end - start) / inc; for(int i = 0; i <= steps; ++i) { cout << (start + (inc * i)) << endl; } } The problem is that the numbers the above program outputs look like this: 0.99999 0.999991 0.999992 0.999993 0.999994 0.999995 0.999996 0.999997 0.999998 0.999999 1 1 1 1 1 1.00001 1.00001 1.00001 1.00001 1.00001 1.00001 They only appear to be correct up to the first 1. What is the proper way to solve this problem?

  Read the article

• Why is this loop over mysql resultset slow? (1.4ms per cycle)

  - by pawpro

  The $res contains around 488k rows the whole loop takes 61s! that's over 1.25ms per cycle! What is taking all that time? while($row = $res->fetch_assoc()) { $clist[$row['upload_id']][$row['dialcode_id']][$row['carrier_id']]['std'] = $row['cost_std']; $clist[$row['upload_id']][$row['dialcode_id']][$row['carrier_id']]['ecn'] = $row['cost_ecn']; $clist[$row['upload_id']][$row['dialcode_id']][$row['carrier_id']]['wnd'] = $row['cost_wnd']; $dialcode_destination[$row['upload_id']][$row['carrier_id']][$row['dialcode_id']]['other_destination'] = $row['destination_id']; $dialcode_destination[$row['upload_id']][$row['carrier_id']][$row['dialcode_id']]['carrier_destination'] = $row['carrier_destination_id']; } Now resultset of 10 rows, smaller arrays and performance 30 times higher (0.041ms) not the fastest still but better. while($row = $res->fetch_assoc()) { $customer[$row['id']]['name'] = $row['name']; $customer[$row['id']]['code'] = $row['customer']; }

  Read the article

• Can I use MFC objects in STL containers?

  - by Jesse Stimpson

  The following code doesn't compile for me in MSVC2005: std::vector<CMenu> vec(10); CMenu is an MFC menu object (such as a context menu). Through some testing I learned that CMenu does not have a public copy constructor. To do what I wanted to do, I needed to use a dynamic array. CMenu* menus = new CMenu[10]; // ... delete [] menus; Of course, now I've lost all the benefits of using an STL container. Do I have any other options?

  Read the article

• Preparing for the next C++ standard

  - by Neil Butterworth

  The spate of questions regarding BOOST_FOREACH prompts me to ask users of the Boost library what (if anything) they are doing to prepare their code for portability to the proposed new C++ standard (aka C++0x). For example, do you write code like this if you use shared_ptr: #ifdef CPPOX #include <memory> #else #include "boost/shared_ptr.hpp" #endif There is also the namespace issue - in the future, shared_ptr will be part of the std, namespace - how do you deal with that? I'm interested in these questions because I've decided to bite the bullet and start learning boost seriously, and I'd like to use best practices in my code. Not exactly a flood of answers - does this mean it's a non-issue? Anyway, thanks to those that replied; I'm accepting jalfs answer because I like being advised to do nothing!

  Read the article

• Storing objects in STL vector - minimal set of methods

  - by osgx

  Hello What is "minimal framework" (necessary methods) of object, which I will store in STL <vector>? For my assumptions: #include <vector> #include <cstring> using namespace std; class Doit { private: char *a; public: Doit(){a=(char*)malloc(10);} ~Doit(){free(a);} }; int main(){ vector<Doit> v(10); } gives *** glibc detected *** ./a.out: double free or corruption (fasttop): 0x0804b008 *** Aborted and in valgrind: malloc/free: 2 allocs, 12 frees, 50 bytes allocated.

  Read the article

• struct with template variables in c++

  - by monkeyking

  I'm playing around with template, so I'm not trying to reinvent the std::vector, I'm trying to get a grasp of templateting in c++. Can I do the following template <typename T> typedef struct{ size_t x; T *ary; }array; What I'm trying to do is a basic templated version of typedef struct{ size_t x; int *ary; }iArray; It looks like its working if I use a class instead of struct, so is it not possible with typedef structs? thanks

  Read the article

• using arrays to get best memory alignment and cache use, is it necessary?

  - by Alberto Toglia

  I'm all about performance these days cause I'm developing my first game engine. I'm no c++ expert but after some research I discovered the importance of the cache and the memory alignment. Basically what I found is that it is recommended to have memory well aligned specially if you need to access them together, for example in a loop. Now, In my project I'm doing my Game Object Manager, and I was thinking to have an array of GameObjects references. meaning I would have the actual memory of my objects one after the other. static const size_t MaxNumberGameObjects = 20; GameObject mGameObjects[MaxNumberGameObjects]; But, as I will be having a list of components per object -Component based design- (Mesh, RigidBody, Transformation, etc), will I be gaining something with the array at all? Anyway, I have seen some people just using a simple std::map for storing game objects. So what do you guys think? Am I better off using a pure component model?

  Read the article

• which is time consuming construct in following program?

  - by user388338

  while submitting a solution for practise problem 6(odd) i got TLE error but while using using print and scanf in place cin and cout my sol was submitted successfully with 0.77s time..i want to know how can i make it more efficient link to problem is codechef problem 6 #include<iostream> #include<cstdio> using namespace std; int main() {int n,N; scanf("%d",&n); for(int l=0;l<n;l++) { scanf("%d",&N); int i=0,x; if(N<=0) continue; for(;N>=(x=(2<<i));i++); printf("%d",x/2); cout<<"\n"; } }

  Read the article

• Correct Exceptions in C++

  - by Dr.Ackula

  I am just learning how to handle errors in my C++ code. I wrote this example that looks for a text file called some file, and if its not found will throw an exception. #include <iostream> #include <fstream> using namespace std; int main() { int array[90]; try { ifstream file; file.open("somefile.txt"); if(!file.good()) throw 56; } catch(int e) { cout<<"Error number "<<e<<endl; } return 0; } Now I have two questions. First I would like to know if I am using Exceptions correctly. Second, (assuming the first is true) what is the benefit to using them vs an If else statement?

  Read the article

• Converting c++ string to int

  - by skazhy

  Hi! I have the following data in a c++ string John Doe 01.01.1970 I need to extract the date and time from it into int variables. I tried it like this: int last_space = text_string.find_last_of(' '); int day = int(text_string.substr(last_space + 1, 2)); But I got invalid cast from type ‘std::basic_string’ to type ‘int’. When I extract the "John Doe" part in another string variable, all works fine. What's wrong? I am trying to compile it with g++ -Wall -Werror.

  Read the article

• boost scoped_lock mutex crashes

  - by JahSumbar

  hello, I have protected a std::queue's access functions, push, pop, size, with boost::mutexes and boost::mutex::scoped_lock in these functions from time to time it crashes in a scoped lock the call stack is this: 0 0x0040f005 boost::detail::win32::interlocked_bit_test_and_set include/boost/thread/win32/thread_primitives.hpp 361 1 0x0040e879 boost::detail::basic_timed_mutex::timed_lock include/boost/thread/win32/basic_timed_mutex.hpp 68 2 0x0040e9d3 boost::detail::basic_timed_mutex::lock include/boost/thread/win32/basic_timed_mutex.hpp 64 3 0x0040b96b boost::unique_lock<boost::mutex>::lock include/boost/thread/locks.hpp 349 4 0x0040b998 unique_lock include/boost/thread/locks.hpp 227 5 0x00403837 MyClass::inboxSize - this is my inboxSize function that uses this code: MyClass::inboxSize () { boost::mutex::scoped_lock scoped_lock(m_inboxMutex); return m_inbox.size(); } and the mutex is declared like this: boost::mutex m_inboxMutex; it crashes at the last pasted line in this function: inline bool interlocked_bit_test_and_set(long* x,long bit) { long const value=1<<bit; long old=*x; and x has this value: 0xababac17 Thanks for the help

  Read the article

• Why can I derived from a templated/generic class based on that type in C# / C++

  - by stusmith

  Title probably doesn't make a lot of sense, so I'll start with some code: class Foo : public std::vector<Foo> { }; ... Foo f; f.push_back( Foo() ); Why is this allowed by the compiler? My brain is melting at this stage, so can anyone explain whether there are any reasons you would want to do this? Unfortunately I've just seen a similar pattern in some production C# code and wondered why anyone would use this pattern.

  Read the article

• Printing escape character

  - by danutenshu

  When I am given "d""\"/""b", I need to print out the statement character for character. (d, b, a slash, a backslash, and 5 quotes) in C++. The only errors that show now are the lines if(i.at(j)="\\") and else if(i.at(j)="\""). Also, how should the outside double apostrophes be excluded? #include <iostream> #include <cstdlib> using namespace std; int main (int argc, const char* argv[] ) { string i= argv[1]; for (int j=0; j>=sizeof(i)-1; j++) { if(i.at(j)="\\") { cout << "\\"; } else if(i.at(j)="\"") { cout << "\""; } else { cout << i.at(j); } } return 0; }

  Read the article

• variadic constructors

  - by FredOverflow

  Are variadic constructors supposed to hide the implicitly generated ones, i.e. the default constructor and the copy constructor? struct Foo { template<typename... Args> Foo(Args&&... x) { std::cout << "inside the variadic constructor\n"; } }; int main() { Foo a; Foo b(a); } Somehow I was expecting this to print nothing after reading this answer, but it prints inside the variadic constructor twice on g++ 4.5.0 :( Is this behavior correct?

  Read the article

< Previous Page | 78 79 80 81 82 83 84 85 86 87 88 89  | Next Page >