I am using a dll written in FORTRAN to do some calculations and here is how I have set up the program. I have created following files:
C++ source files:
main.cpp
File1.cpp
Header Files:
Datamain.h
DataFile1.h
[Code]....
Here are my questions:
1) I actually want to call Sub2dll from the main program. But the above program does not build and it gives me the following error: In function 'int main()': Sub2dll was not declared in this scope.
When I build this program with the call to Sub2dll in main commented out and instead put that call in File1::Setup function things build well and runs giving the answer expected. How can I make the call to Sub2dll from main.
2) I am including "Datamain.h" in main. However when I build it with out the declaration int Datamain::Index; in main, it gives me the following error: undefined reference to Datamain::Index When I add that declaration to main the error disappears.
I am usiing Code::blocks with MinGW compiler. I have not put the argument list for the subroutine calls since there were not errors in that part.
I have this sample code, that calls a function in a DLL. The function Callback is provided to the DLL as an argument, in order for the DLL to notify my program of relevant changes.
I would like to change this code, so that there is a Main class that opens the connection and there are several separate classes (as below) that register themselves for a specific variable and get notifications if that value is changed. The reason for this is that I want to get several notifications for several independent events and I don't want them to mix. I figured this should look something like this:
Unfortunately this gives me an error: error: cannot convert 'InAClass::Callback' from type 'void (InAClass::)(AmsAddr*, AdsNotificationHeader*, long unsigned int)' to type 'PAdsNotificationFuncEx {aka void (__attribute__((__stdcall__)) *)(AmsAddr*, AdsNotificationHeader*, long unsigned int)}'
At first I thought this was because I don't have the namespace "using namespace std;" on top, but then I should be able to find something that specifically needs to come from the std namespace and is not marked as such. I don't want to rule the option out, but so far I could not find anything like that.
An alternative explanation might be that the Callback function needs to be global, but if I make it global, how can I distinguish between several Callback functions?
class TestClass { private int x = 10; TestClass a = new TestClass();
[Code].....
I know this is recursion but how do the compiler do this? How can it call itself when it hasnt even completed initializing every object it has? Why do VS allow this?
So I am wondering how I would go about calling a function for all instances of an object. I tried googling it, but all I saw was solutions like making an array of pointers to the objects. What if I don't know how many objects there will be? Isn't there an easier way?
How do I call these functions from Mechanical.h???
Mechanical.h #ifndef MECHANICAL_H_ #define MECHANICAL_H_ class statics { public:
template<class T> struct Inertia_types { T Rec(T _x, T _y); T Tri(T _x, T _y);
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I am trying to create templated functions which I can apply all data types to except for strings and other types such as wchar. Am I also writing these correctly? This is my first attempt ever doing this.
Just a few moments ago i was just doing foolish things in c++ and discovered something new. Though some of you might have known this, for those who dont know, take a look at the follwing 2 small programs,
so here is my problem. i think u wud have figured out what m trying to do above. am actually calling the main() of the class and from there, i want to call the usual main... the problem is, during A.main()'s run, if i refer to main(); , that call represents itself, that it, it is like it calls itself. How on earth can i call the outside main?
Every time I try to use the function SaveNewCD, it doesn't write to file correctly. It writes the ~, three characters, then goes into an infinite loop.
#include<iostream> #include<fstream> using namespace std; int SaveNewCD(); int OpenCD(); int main() { char ArtistName[25];
I am trying to use ofstream to write in a txt file in a function called recurrently. for a simplified example:
void func_write(double x) { ofstream myfile; myfile << "the result = " << x << endl; } int main() { ofstream myfile;
[Code] .....
To this stage, it does not work, because the myfile in func_write cannot write in the txt file opened in main function. I don't want to open, append and close the txt file each time the function is called, that will take more time to execute all (imagine with 500 calls).
Allow users to enter their name and favorite saying in a single method that gets invoked two times. If I can only return one value at a time, how am I suppose to get name and favorite saying out of UserInput()?
I want to update a label from Form2. When I click on the button on Form 2, the textbox on Form2 should update the label on Form1 and take me to a certain website. What ever URL is typed into the textbox on Form2 is what website URL the label on Form1 will take me to. The label on Form1 can say something such as You can check out my website here!!! and when they click on the saying it takes me to their website.
I created 3 Rectangle pointers. And later in the program, I would like to modify these existing Rectangles by calling constructors with parameters. Is this possible? I have a sense that it involves creating overload operators, but I am not sure how to do it, or if that's the correct path.
#include <iostream> #include <string> using namespace std; // Base class class Shape { protected: int width; int height;
I would like to call a script from a makfile to glean some information about the OS. What I more or less need is the OS name and version (CentOS-5.9, OPENSUSE-12.2, Cygwin, etc). I think I can get the rest of what I need from uname. The OS name and version doesn't seem to reside in any consistent place over the various Linux flavors. I also need to get the version of the gnu c compiler, since I think that may also require a bit more involved scripting than I would like to try out of make.
The main question is weather I can call a script out of make and have it return a value for a variable.
I'm new to C/C++. I'm trying to make a program that's going to use the CBLAS libraries that I downloaded on BLAS. After fighting tooth and nail with VC 2005 (I downgraded on purpose because at one point I was desperate.) with regards to solving compilation errors and such and eventually it all compiled just fine.
The problem now is, I get the above mentioned error. It says: "Unhandled exception at 0x0040271c in Try.exe: 0xC0000005: Access violation reading location 0x4e18feb8."
Now there are a few .cpp files (I'm compiling as C code.) which contain the functions and there is one other one which contains my main method. Using the debugger, it goes through 3 files all in all.
Every time we pass an object to a function, and when the function ends and the object is not necessary anymore the destructor is called. if it's passing by value then a copy of the object is passed. if the object has a pointer inside of it so we implement the copy constructor to create a new pointed-variable so the original pointer will not get deleted.
so far so good. But what about passing an object to a non-member function by reference?
The language says that as soon as the function ends - the object will be deleted , because we passed by ref. that means that after the function ends - the object is not usable anymore! =What does that say? that in c++ you can't pass object by ref. because it will get deleted and un-uasable??
Varifying it with a compiler shows that the object is NOT deleted after the function ends.
Code: const MenuData breakfast[NUMOFBREAKFASTITEMS] = { {"Egg Breakfast", "Two eggs with a side of bacon and two slices of toast.", "", "2 Eggs, 2 Toats, 2 Bacons", "", 250.00}, {"Pancake Breakfast", "Three Buttermilk pancakes served with butter and syrup.", "", "Three Pancakes, Butter, Syrup", "", 200.00},
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What I'm trying to do is call the printReceipt function in the main, but I'm doing it wrong. Here is my attempt.
I haven't tried to run my program yet, but maybe I will save some trouble if I ask this question first.I am using MC PIC16F690, and I could make a pin high or low by writing RCx = 1 or 0, where x is the pin in the C port. However, I want to use the counter variable from a for() loop as the pin number. Will RC(variablename) = 1 work, or is there another syntax?
I have i want to call a function with two results for example x = 1 and y = 2.How do i return this function in c and how do i call such a function in the main program.
I am trying to get this statistical equation to work. m! / n! (m-n)!.
Code: #include <stdio.h> long factorial_M(long); // function prototype // long factorial_N(long); long total (long); int main(int argc, const char * argv[]) {
I have a vector of pointers inside a seperate Exam class.
vector <Question* > question_list
The Question class is my base class in which I have derived sub classes for the different types of questions (MultipleChoice, LongAnswer, etc.). I am using my vector to hold the different types of questions.
in each of those classes I have virtual "write" functions in both the base and the derived classes, that write to a file differing for each type of question.
My problem now is calling the write function from a Exam function. I've tried several methods, such as:
for (size_t i = 0; i < question_list.size(); i++) { question_list[i].write(testfile.c_str()); }
but it comes with two errors: "error C2228:left of '.write' must have class/struct/union" along with "IntelliSense: expression must have class type"
I have made a write function for the exam class as well but am not sure what it should include since the Exam class is not a derived class of the Question class.
