c++

[C++] Index strings by other strings

Hello, I need to index specific strings with other strings and I can't really find a good way to do so. I tried to use tr1::unordered_map, but I'm having some difficulties using it. If someone could tell me what is the best way to do that I'd be really grateful :) I also need to index objects by a number (numbers are not in order so I ca...

error on compiling statically linked library created in Qt

we have created a statically linked library in Qt.On compiling the library we are getting errors...like QImage: no such file or directory and why start timer etc... ...

c++ signatures, pointers

Hello, what's the difference between these signatures? T * f(T & identifier); T & f(T & identifier); T f(T & identifier); void f(T * identifier); void f(T & identifier); void f(T identifier); I met pointers in c, but the amperstand in function signature is new for me. Can Anyone explain this? ...

Animated Image in Win32

Hello. How can i put an animated GIF to my dialog in my native Win32 application? I have a loading indicator, and a loading process. Thanks :-) ...

Where to Declare Structures, etc?

Should all structs and classes be declared in the header file? If I declare a struct/class in a source file, what do I need to put in the header file so that it can be used in other files? Also, are there any resources that show some standard practices of C++ out there? ...

C++ Vector at/[] operator speed

In order to give functions the option to modify the vector I can't do curr = myvec.at( i ); doThis( curr ); doThat( curr ); doStuffWith( curr ); But I have to do: doThis( myvec.at( i ) ); doThat( myvec.at( i ) ); doStuffWith( myvec.at( i ) ); (as the answers of my other question pointed out) I'm going to make a hell lot of calls ...

wstring in union

Hi, I'd like to define a union, for reading special kind of binary files. The union should have two members one of int and the other a kind of string, or any other that's the question; what is the best way to do this? union uu { int intval; wstring strval; uu(){ memset(this, 0, sizeof(this)); } } it says: "Member ...

strftime doesnt display year correctly

Hi guys, i have the following code below: const char* timeformat = "%Y-%m-%d %H:%M:%S"; const int timelength = 20; char timecstring[timelength]; strftime(timecstring, timelength, timeformat, currentstruct); cout << "timecstring is: " << timecstring << "\n"; currentstruct is a tm*. The cout is giving me the date in the correct forma...

python challenge, but for C++

Does anyone know any site or book that presents problems like python challenge, but for C++? When I think python challenge, I do not mean only a set of problems to be solved with C++ (for that I could probably use the same problems of python challenge), but rather problems that will probably be best solved using C++ STL, special feature...

Dynamic binding in C++

I'm implementing a CORBA like server. Each class has remotely callable methods and a dispatch method with two possible input, a string identifying the method or an integer which would be the index of the method in a table. A mapping of the string to the corresponding integer would be implemented by a map. The caller would send the stri...

Value get changed even though I'm not using reference

In code: struct Rep { const char* my_data_; Rep* my_left_; Rep* my_right_; Rep(const char*); }; typedef Rep& list; ostream& operator<<(ostream& out, const list& a_list) { int count = 0; list tmp = a_list;//----->HERE I'M CREATING A LOCAL COPY for (;tmp.my_right_;tmp =...

GDB skips over my code!

So, I've defined a class like DataLoggingSystemStateReceiver { DataLoggingSystemStateReceiver() : // initializer list { // stuff } // ... other functions here }; In main, I instantiate DataLoggingSystemStateReceiver like so: int main() { // ... run stuff Sensor sensor(port, timer); DataLoggingSystemStateReceiver...

A matter of style

Would you write something like: enum XYZ_TYPE {X=1, Y=2, Z=3}; I saw it and the suffix _TYPE confuses me in the enum context. There is a strong prospect that it is because I am not bright. ...

C++ design question on traversing binary trees

I have a binary tree T which I would like to copy to another tree. Suppose I have a visit method that gets evaluated at every node: struct visit { virtual void operator() (node* n)=0; }; and I have a visitor algorithm void visitor(node* t, visit& v) { //do a preorder traversal using stack or recursion if (!t) return; v(t); v...

Signedness of enum in C/C99/C++/C++x/GNU C/GNU C99

Hello Is enum type signed or unsigned? Is the Signedness of enums differ in C/C99/ANSI C/C++/C++x/GNU C/ GNU C99? Thanks ...

Incorrect logic flow? function that gets coordinates for a sudoku game

This function of mine keeps on failing an autograder, I am trying to figure out if there is a problem with its logic flow? Any thoughts? Basically, if the row is wrong, "invalid row" should be printed, and clearInput(); called, and return false. When y is wrong, "invalid column" printed, and clearInput(); called and return false. When ...

Incorrect emacs indentation in a C++ class with DLL export specification

I often write classes with a DLL export/import specification, but this seems to confuse emacs' syntax parser. I end up with something like: class myDllSpec Foo { public: Foo( void ); }; Notice that the "public:" access spec is indented incorrectly, as well as everything that follows it. When I ask emacs to describe the syntax at ...

How to free memory from a list of classes

Say I have two classes created work and workItem. CWorker *work = new CWorker(); CWorkItem *workItem = new CWorkItem(); The work class has a public list m_WorkList and I add the work item to it. work->m_WorkList.push_back(workItem); If I just delete work if(work != NULL) delete work; Do I need to loop through th...

Ctor not allowed return type.

Having code: struct B { int* a; B(int value):a(new int(value)) { } B():a(nullptr){} B(const B&); } B::B(const B& pattern) { } I'm getting err msg: 'Error 1 error C2533: 'B::{ctor}' : constructors not allowed a return type' Any idea why? P.S. I'm using VS 2010RC ...

graphics programming

hi , i would like to program some graphic figures such as line, circle,etc. i have used turboc++ 3.0 for dos graphics. i would like to do the same with the compilers dev c++ or code blocks or vc++. i would like to implement dda and bresenhems line and circle drawing algorithm. how should i go about implementing these programs through ...